Thierry Lang

Jérôme Wittwer

Caroline Berchet

Michele Cecchini

Valerie Moran

da s le ad e d u t a ail personnel ou en collaboration avec les co-auteurs des articles.

Social inequalities in health-related behaviours: Summary/Résumé Is the grass greener on the other side? vii Summary Social Inequalities in Health-Related Behaviours:

Is the grass greener on the other side?

This thesis deals with social inequalities in health-related behaviours such as lifestyle risk factors for health (precisely, obesity and alcohol consumption), and the utilisation of health care services, in a number of OECD countries. This work relies on a micro-econometrics approach, using a range of national health survey data. This thesis aims to (a) compare social inequalities in health-related behaviours across countries with different characteristics; (b) contribute to the understanding of social disparities in healthrelated behaviours; and (c) examine how self-reporting in surveys may affect the rating of behavioural risk factors, and therefore affect the measurement of social inequalities. This thesis is composed of six sections and relies upon four articles submitted or published in peerreview journals. The general introduction provides some background on health inequalities with an emphasis on the role of the determinants of health inequalities and the contribution of international comparisons.

Chapter 1 presents the data sources used for 23 OECD countries, issues of cross-country comparability and survey data limitations. In a second step, it describes the methods applied to measuring inequalities in cross-country comparisons.

Chapter 2 examines inequalities in obesity and overweight by education level and by socioeconomic status in 11 countries, and was published in the European Journal of Public Health in 2013.

In addition, a range of analyses conducted for Australia, Canada, France, England and Korea are undertaken with the aim of exploring the relationship between education and obesity. This work was published in the OECD Economics Journal in 2011.

Chapter 3 focuses on disparities in hazardous drinking across education levels and socioeconomic groups in 13 countries. The analysis aims to examine social disparities in risky alcohol consumption as reported in surveys, and assesses how self-report bias may affect social inequalities in drinking. This work was submitted to the European Journal of Public Health in 2014.

Social inequalities in health-related behaviours: Summary/Résumé Is the grass greener on the other side? viii Chapter 4 investigates inequities in health care service utilisation in 18 countries, and tries to examine the role of health system features as potential determinants of these inequalities. The analysis focuses on doctor and dentist visits, and breast and cervical cancer screening. This study was published in the European Journal of Health Economics in 2013.

Finally, the general conclusion provides a discussion of the main findings, proposes recommendations for research, and discusses policy implications.

Social inequalities in health-related behaviours: Summary/Résumé Is the grass greener on the other side? ix

Résumé conséquent en français

Inégalités Sociales des Comportements de Santé:

L'herbe est-elle plus verte ailleurs?

Cette thèse traite des inégalités sociales en matière de comportements de santé tels que les modes de ie li s à la sa t sp ifi ue e t, l o sit et la o so atio d al ool et l utilisatio des se i es de sa t , da s plusieu s pa s de l OCDE. Ce t a ail repose sur une approche micro-économétrique et utilise un grand nombre de bases de données nationales. Les objectifs de cette thèse sont de: (1) comparer les inégalités sociales de comportements de santé entre des pays ayant des caractéristiques différentes, (2) apporter un éclairage à la compréhension des disparités sociales des comportements de sa t , et e fi e a i e o e t l auto-déclaration dans les enquêtes peut affe te l aluatio des comportements de santé, et donc affecter la mesure des inégalités.

Contexte

Les dispa it s d tat de sa t esu es pa la o talit ou o idit o t la ge e t t documentées dans la littérature internationale vis-à-is du ge e, l eth i it , l o igi e so iale, l du atio , le statut socio-économique et la zone géographique (van Doorslaer et al., 1997 ;Mackenbach et al., 2008 ;OCDE 2011). Les études sur les disparités de mortalité et de morbidité selon le statut socioéconomique montrent notamment que les individus les plus défavorisés meurent prématurément comparé aux plus favorisés, et que les populations les plus pauvres, les plus vulnérables, sont plus affectées par les maladies. Eurostat (2010) a commencé à mesurer de façon régulière les disparités d esp a e de ie pa i eau d du atio da s les pays européens. Les dernières données montrent que l a t d esp a e de ie à a s selo le i eau de diplô e a ie de , a es hez les fe es e

Slovénie à 17 années chez les hommes en Estonie. (Jusot et al., 2013). En outre, ces inégalités sont ita les puis u u e eilleu e d fi itio des i te e tio s politi ues peut aide à les dui e Wood a d et Kawachi, 2000). Deuxièmement, les inégalités de santé peuvent avoir un impact sociétal plus large que les seuls résultats sur la santé, notamment en termes de bien-être global et de résultats sur le marché du t a ail, du fait u u au ais tat de sa t est asso i à u e fai le ussite s olaire et à de mauvais résultats sur le marché du travail. Mackenbach et al. (2010) estiment que les pertes sociales liées aux inégalités de santé atteignent 9,4% du PIB. Pour ces raisons, les gouvernements prêtent de plus en plus attention à la mesure et la compréhension des inégalités de santé, cherchant les moyens les plus appropriés pour les réduire.

Les déterminants des inégalités de santé

L tat de sa t est i flue pa de o eu d te i a ts : caractéristiques génétiques, facteurs individuels et contextuels. Les facteurs individuels font référence aux conditions sociales et aux choix i di iduels, o e les o ditio s de ie et d e ploi, le i eau d du atio , le statut so io-économique, l i t g atio à la ie so iale, les o po te e ts et odes de vie liés à la santé (comme la consommation de ta a et d al ool, l ali e tatio et l a ti it ph si ue , ai si ue la de a de de soi s de sa t . Les facteurs contextuels font eux référence à de multiples dimensions environnantes comme la richesse nationale, les i galit s de e e u, les a a t isti ues des s st es de sa t e . l off e de soi s, l a s

Social inequalities in health-related behaviours:

Summary/Résumé Is the grass greener on the other side? xi gratuit aux soins, les politiques de prévention), les normes sociales, et les facteurs environnementaux (ex. transport et pollution). Tous ces détermina ts o t u effet su l tat de sa t , et les i te a tio s e t e ceux-i peu e t i flue e l tat de sa t plus ou oi s fo te e t. La o p he sio des i galit s de santé repose largement sur la compréhension des relations entre les facteurs socio-économiques, les o po te e ts et la sa t . Le ad e d a al se de ette th se p opose d tudie les i galit s so iales da s les odes de ie et da s l utilisatio des se i es de sa t o e o e de t aite les i galit s sociales de santé. Comme montré ci-dessous, e ad e d a al se est oh e t a e le od le de

Grossman et ses extensions.

2.1 Cadre théorique Grossman (1972[START_REF] Grossman | The Human Capital Model[END_REF] a développé un cadre économique pour la demande de santé basé sur la théorie du capital humain. Dans ce modèle, la santé est un capital ui d pe d d u sto k i itial et se déprécie avec le temps, mais peut être augmenté avec un investissement en santé. Les individus sont des producteurs actifs de leur santé et cherchent à maximiser leur utilité en achetant des biens (ex. soins de santé, alimentation) et en combinant ceux-i a e leu te ps dispo i le. L du atio a oît l effi ie e de la p odu tio de sa t a les i di idus les plus du u s g e t ieu l i fo atio li e à la sa t , et font de meilleurs investissements en santé. Le modèle de Grossman donne un cadre théorique pour la p di tio de la sa t e fo tio de l du atio et du statut so io-économique, qui sont positivement eli s à l i estisse e t e sa t . Ai si, le od le de G oss a est u e ase solide pou l a al se des inégalités de santé (Galama et [START_REF] Van Kippersluis | al ool e F a e: uelles so t les populations à risque ? IRDES Questio d'Éco o ie de la Santé 129[END_REF].

L i estisse e t e sa t ta t u o ept l da s e od le, les odes de ie et les p f e es i di iduelles joue t u ôle i po ta t da s e ad e th o i ue. Plusieu s tudes o fi e t l i pact des modes de vie liés à la santé sur les inégalités sociales de santé (McGinnis et Foege, 1993 ;Contoyannis et Kones, 2004 ;Stringhini et al., 2010). Cependant, les modes de vie à risque pour la santé peuvent o t i ue à l tat de sa t de diff e tes façons. Alors que la consommation de tabac contribue la ge e t au g adie t ie o u des i galit s so iales de sa t , la o so atio d al ool peut pa fois contraster. [START_REF] Van Kippersluis | al ool e F a e: uelles so t les populations à risque ? IRDES Questio d'Éco o ie de la Santé 129[END_REF] ont examiné pourquoi les plus riches boivent davantage et fument moins que les plus pauvres, et proposé une théorie sur les modes de vie expliquant pourquoi les plus i hes s e gage t plus da s des o po te e ts à is ue od et oi s da s des o po te e ts à risque élevé pour la santé.

Social inequalities in health-related behaviours:

Summary/Résumé Is the grass greener on the other side? xii Dans le modèle de G oss a , l du atio et le statut so io-économique sont corrélés à la santé.

Cette o latio a t la ge e t alid e da s les tudes e pi i ues. Cepe da t, l e iste e d u e elatio ausale este dis ut e. Le p o l e est d ide tifie si le g adie t social de santé reflète un lien causal du statut socio-économique vers la santé, ou une causalité inverse de la santé vers le statut socioéconomique. Cette question a été étudiée dans la littérature et différents résultats émergent. Les conclusions des études vont dans les deux directions, montrant par exemple que la santé influence l e ploi Mo is,

; Lundborg et al., 2010 ;Burton et al., 1998) et que le travail influence la santé (Llena-Nozal, 2009 ;Robone et al., 2011). À propos de cette derniè e asse tio , ie ue l i pa t du t a ail su la sa t appa aisse t e positif da s e tai es tudes et gatif da s d aut es, u e e tai e o e ge e des sultats sugg e ue l effet gatif est li à des situatio s où les e plo s o t pas de contrôle sur la quantité de travail à fournir (Bassanini et Caroli, 2014).

U e di e sio i po ta te elati e à l tude des i galit s de o po te e ts de sa t o espo d aux préférences individuelles, à savoir si les individus donnent plus de valeur à une satisfaction i diate plutôt u au o s ue es à lo g te e de leu s omportements de santé. En ce qui concerne les comportements addictifs liés à la santé, les individus doivent souvent faire un compromis entre la satisfaction immédiate résultant de la consommation de biens nocifs pour leur santé (ex. tabac, alcool, produits gras et sucrés) et une perte future de capital santé. Des modèles économiques pour les ie s addi tifs o t t d elopp s à l o igi e pa Be ke et Mu ph i t oduisa t la th o ie de l addi tio atio elle ui suppose ue le o so ateu est o s ient des conséquences futures de sa consommation de biens addictifs et prend ces effets en compte en faisant ses choix. Ce modèle repose su l id e ue les p f e es a tuelles pou les ie s addi tifs d pe de t des o so atio s pass es et futures de ces ie s. Plusieu s tudes e pi i ues ie e t o fi e la th o ie de l addi tio atio elle (Chaloupka et Warner, 2000 ;Clark et Etilé, 2002).

Les p f e es i di iduelles so t o l es à l du atio et au statut so io-économique, mais il y a peu de résultats sur la direction de la causalité. Les individus ayant une préférence pour le futur i estisse t plus da s l du atio et opte t da a tage pou des o po te e ts fi ues pou la sa t (Fuchs, 1982). De la même façon, les personnes les moins éduquées et les plus pauvres ont une préférence pour le présent plus marquée que les personnes les plus aisées (Becker et Mulligan, 1997). La connexion entre préférences individuelles, comportements de santé, et éducation a donc toute son i po ta e da s l tude des inégalités sociales des comportements de santé. Les préférences Social inequalities in health-related behaviours:

Summary/Résumé Is the grass greener on the other side? xiii individuelles peuvent affecter les relations entre éducation et santé en jouant un rôle de médiation des inégalités sociales de santé comme le suggère la littérature (van de Pol, 2011 ;Jusot et Khlat, 2013).

Les inégalités sociales dans les comportements de santé

Le ad e d a al se de ette th se p opose d tudie les i galit s so iales elati es au odes de ie et à l utilisatio des se i es de sa t o e o e de t aite les i égalités sociales de santé. En effet, dui e les i galit s da s les odes de ie et da s l utilisatio des se i es de sa t peut aide à lutter contre les inégalités sociales de santé en général.

Les différences sociales de mortalité et de morbidité peuvent être directement liées aux conditions de vie (ex. profession ayant un risque inhérent de cancer), mais elles peuvent aussi émerger de différences de modes de vie ou de différences de recours aux soins entre groupes sociaux. Les modes de vie jouent un rôle important dans le lien entre santé et facteurs socio-économiques. Ils sont souvent i flue s pa l du atio et le statut so io-économique ; et en même temps, ils contribuent au développement de maladies chroniques (ex. maladies cardiovasculaires, diabète, cancers, santé mentale, maladies musculo-s ueletti ues et affe te t ai si la sa t et la lo g it . De e, l a s au soi s est tout aussi important dans le processus de détermination des inégalités de santé. Par exemple, les personnes à hauts revenus ont un meilleur accès aux services de santé, ce qui se traduit par des différences de résultats de santé liées au niveau de revenus.

Ai si, dui e les i galit s so iales de sa t el e o seule e t d effo ts pou a lio e les sultats de sa t des populatio s les plus d fa o is es, ais aussi d effo ts pou dui e les i galit s da s les odes de ie et da s l utilisatio des se vices de santé. Outre les comportements liés à la santé, des facteurs externes peuvent interagir. On pense notamment aux facteurs contextuels et environnementaux tels que les caractéristiques des systèmes de santé (ex. densité des services médicaux, systèmes de paiement), normes sociales, transport et pollution.

.

L'apport des co paraiso s i ter atio ales .1 L'i porta ce des co paraiso s i ter atio ales

Social inequalities in health-related behaviours:

Summary/Résumé Is the grass greener on the other side? xiv Cette th se s i t esse à la esu e et à la o pa aiso des i galit s so iales des o po te e ts de sa t , a e pou o je tif d a oi u e utilisatio app op i e des a al ses ulti-pays. Les études i te atio ales pe ette t au d ideu s politi ues d app e d e des pa s oisi s les o es p ati ues et de o p e d e l i pa t des politi ues, ie ue ela e soit pas sans difficultés.

Les études internationales peuvent aider les pays à développer leur connaissance et leur o p he sio , et elles fa o ise t l i t ospe tio et pe ette t des ha ge e ts da s la a i e de pe se et d ide tifie les p o l es. Les évaluations multi-pays permettent de dresser un tableau précis de la situatio et d ide tifie où so t les p o l es, o e t les aut es pa s g e t eu -ci, quels pays réussissent mieux, pourquoi et comment. Les comparaisons internationales offrent aussi une base pour l a al se des elatio s e t e pe fo a e des pa s et politi ues, et plus p is e t, elles off e t u e sou e de o aissa e et des p eu es pou u e eilleu e o p he sio de l i pa t des politi ues publiques. Cependant, ce travail s a o pag e ie sou e t de diffi ult s. E effet, des p o l es conceptuels et pratiques peuvent émerger comme par exemple des problèmes liés à la disponibilité et à la comparabilité des données, ou encore aux différences dans les caractéristiques institutionnelles des pays.

Cette th se s i t esse au aspe ts a al ti ues et thodologi ues de l aluatio e t e pa s plutôt u au o pa aiso s des politi ues. Ce t a ail essa e pas de pe to ie les politi ues atio ales en place ou de proposer un ensemble de bonnes pratiques. En revanche, il a pour but de dresser un ta leau p is des i galit s e t e pa s, e olle ta t des do es d e u tes atio ales, e da t les données homogènes entre pays, et développant des mesures comparables. De plus, cette thèse soulève des uestio s thodologi ues et des uestio s autou de l i te p tatio des sultats afi d a lio e les recommandations en termes de politiques.

Étude des inégalités de santé entre pays

Il existe deux initiatives au niveau européen, initiées dans les années 1990, qui ont pour but de mesurer et de comprendre les inégalités de santé (Jusot, 2010). Financés par la Commission Européenne, es deu p ojets ette t e lu i e l e iste e d i galit s de sa t et de g a des a iatio s e t e pa s.

Ces p ojets s i t esse t aussi au i galit s elati es au odes de ie et à l utilisatio des se i es de santé. dimensions suivantes : iniquité dans le financement de la sa t , i i uit da s l off e de soi s, i i uit da s l utilisatio des se i es de sa t , et i galit s d tat de sa t . L a tuel projet ECuity III s i t esse en outre aux déterminants de la demande de soins de santé et aux relations causales (ex. impact des i galit s de e e u, de l assu a e p i e, des estes à ha ge des patie ts pou ieu aide à la décision politique.

U e e te sio du t a ail ECuit au pa s de l OCDE a pe is de ou i u plus la ge e tail de pays (van Doorslaer et Masseria, . Cette tude po ta t su les i i uit s d utilisatio des soi s de santé par niveau de revenus, a ou e t pa s de l OCDE u g a d o e de pa s eu op e s ai si ue l Aust alie, le Ca ada, le Me i ue, et les U"A . Ce p ojet a is e lu i e des i iquités en faveur des plus pauvres pour les visites de médecins généralistes, et en faveur des plus riches pour les visites de spécialistes, dans plusieurs pays.

Enfin, il est important de souligner que ces projets ne pourraient exister sans les efforts mis en diff e es d esp a e de ie pa i eau d du atio afi de pe ett e le sui i des i galit s de sa t .

Ces travaux sur la mesure et la compréhension des inégalités de santé et sur les pistes possibles pour les réduire ouvrent de nouvelles voies de recherche. Par exemple, l i lusio de pa s o -Européens

Social inequalities in health-related behaviours:

Summary/Résumé Is the grass greener on the other side? xvi dans les comparaisons internationales apparaît nécessaire. De plus, les champs de la statistique et de l o o t ie e esse t de se d eloppe et de ou elles te h i ues peu e t a lio e les e he hes précédentes. De ou eau d eloppe e ts su la esu e des i galit s pe ette t d a lio e l aluatio da s le ad e de o pa aiso s ulti-pa s. Pa e e ple, lo s u o a al se les i galit s so iales de sa t e o pa aiso i te atio ale, il est esse tiel d utilise des outils appropriés pour comparer les inégalités entre pays ayant des caractéristiques différentes (ex. structure de la population, dist i utio du i eau d du atio et de la lasse so iale . Des esu es ag g es des i galit s telles ue l i di e de o e t atio et les i di es elatifs et a solus d i galit ai si ue leu s e tes e te sio s, sont utilisés pour faire face à ce problème.

Études multi-pays sur les inégalités de comportements de santé

Ce travail est par ailleurs motivé par le besoin d u e o aissa e app ofo die de l te due des inégalités des comportements de santé dans un contexte international, et ceci dans le but de développer les i st u e ts politi ues effi a es isa t les odes de ie. Il e iste assez peu d tudes su les disparités sociales des comportements de santé en comparaison internationale. Bien que les inégalités de santé aie t t la ge e t e plo es pou u g a d o e de a ia les de sa t , assez peu d tudes se so t focalisées sur les comportements à risque. Une des raisons principales est que les modes de vie sont Néanmoins, la littérature dénombre un nombre c oissa t d tudes s i t essa t au i galit s so iales elati es à l o sit Ma ke a h et al., 2008;Costa-Font et al. , à l ali e tatio et à l a ti it physique (Gordon-Larsen et al., 2006;Filippidis et al., 2014), à la consommation de tabac (Cavelaars et al., 2000;Mackenbach et al., , ais t s peu d tudes elati es à la o so atio d al ool.

E out e, le p o l e de l auto-déclaration soulève la question de savoir si le biais de déclaration affe te ait l app iatio des o po te e ts i di iduels, et le as h a t, si e iais a ie ait selo le groupe socio-économique et par conséquent affecterait les mesures des inégalités sociales. Quelques tudes s i t esse t au iais de d la atio et à la esu e des i galit s elati es à l o sit Ca le , 2000; Lakdawalla et Philipson, 2002;Ljungvall et al. 2012;[START_REF] Costa-Font | Income inequalities in unhealthy lifestyles in England and Spain[END_REF]. En particulier, Ljungvall et al.

o t e t à pa ti de do es suisses ue les dispa it s so iales elati es à l o sit so t

Social inequalities in health-related behaviours:

Summary/Résumé Is the grass greener on the other side? xvii affectées par un biais de déclaration chez les femmes mais pas chez les hommes. [START_REF] Costa-Font | Income inequalities in unhealthy lifestyles in England and Spain[END_REF] confirment ce résultat sur do es espag oles o t a t ue les i galit s d o sit so t plus a u es après correction du biais de déclaration, notamment chez les femmes. Cependant, à ma connaissance, il a pas de e he he pu li e su l effet des iais de d la atio su les i galités sociales dans la o so atio d al ool.

L tude su l a s au soi s ie t o pl te l a al se des i galit s des odes de ie. La se tio p de te a o t ue les i galit s de o talit et de o idit pou aie t sulte d i galit s relatives au odes de ie et à l utilisatio des se i es de sa t . Des tudes a t ieu es e es autou des années 2000 ont montré que dans un grand nombre de pays les individus à hauts revenus avaient plus de chance de consulter un médecin (en particulier, un spécialiste et un dentiste) et de faire un dépistage de cancer que les individus à bas revenus, ceci étant vrai pour un même niveau de besoin de soins de santé [START_REF] Van Doorslaer | Income-related Inequality in the Use of Medical Care in 21 OECD Countries[END_REF]Or et al., ;[START_REF] Bago D U A | Measu e e t of Ho izo tal I e uit i Health a e Utilisation Using European Panel Data[END_REF]. Néanmoins, depuis , e tai es fo es o t t ises e pla e da s le ut de dui e les i galit s d a s au soins (ex. système de gatekeeping, réduction de copaiement, programme de dépistage gratuit). Ainsi estil nécessaire de réévaluer les i galit s d utilisatio des se i es de sa t et d a al se es i galit s e lie a e les a a t isti ues des s st es de sa t . Da s le ut d lai e la d isio politi ue, il appa aît e effet i t essa t d ide tifie uelles a a t isti ues des systèmes de santé sont associées à un faible deg d i galit .

. L'apport de cette thèse

Questions de recherche

À t a e s l o je tif g al d e a i e les i galit s so iales des o po te e ts de sa t da s différents pays, cette thèse cherche à répondre à trois questions de recherche portant sur des aspects méthodologiques et sur les implications politiques des inégalités sociales des comportements de santé.

Ces trois questions de recherche sont les suivantes :

 Comment peut-on comparer les inégalités sociales de santé entre pays ayant des a a t isti ues diff e tes pa e . st u tu e de la populatio , dist i utio du i eau d du atio et du statut socio-économique) ?

Social inequalities in health-related behaviours:

Summary/Résumé Is the grass greener on the other side? xviii  Au-delà de l o se atio et du o t ôle des dispa it s so iales de sa t , uel éclairage peut-on apporter sur la compréhension de ces inégalités ? Et, comment mieux informer les décideurs politiques ?

 Comment le biais de déclaration affecte-il l aluatio des o po te e ts de sa t ? Est-ce que le biais de déclaration varie selon les groupes sociaux et affecte par conséquent la mesure des inégalités sociales?

Les principaux résultats

Cette th se t aite des i galit s so iales elati es au odes de ie et à l utilisatio des se i es de xxii pla e u e oo di atio e t e les i ist es et, e pa ti ulie , de s e te d e su les odalit s de financement (ex. qui paie ? qui perçoit les bénéfices ?).

T oisi e e t, le ad e d a al se de ette th se suppose ue l o je tif de réduction des inégalités sociales est réalisable dans une certaine mesure en se concentrant sur les inégalités de comportements de sa t . E pa ti ulie , les odes de ie tels ue l o sit et la o so atio de ta a et d al ool, peuvent être directement ciblés par les gouvernements pour améliorer les résultats de santé. Les gouvernements peuvent en effet réduire les facteurs de risque liés aux modes de vie par le biais de politiques cherchant à cibler les comportements à risque pour la santé, telles que les politiques de promotion de la santé ou politiques de régulation. À propos des politiques de promotion de la santé Pa e e ple, l i dust ie ag o-ali e tai e peut joue u ôle da s la lutte o t e l o sit e efo ula t le o te u des p oduits, est le as pa e e ple e Ho g ie ap s l i pl e tatio de la ta e su les produits gras et sucrés, et aux Pays-Bas ap s l i stau atio de l ti uetage nutritionnel obligatoire.

À propos des politiques de régulation, les gouvernements peuvent employer des mesures de ta atio s, gulatio de la pu li it , et est i tio s g og aphi ues et ho ai es pou le ta a et l al ool .

Pa e e ple, pou o t e l obésité, la France, la Hongrie et le Mexique ont mis en place une taxe sur les boissons sucrées. Une inquiétude vis-à-vis des mesures de taxation relève de leur impact régressif sur les individus à bas revenus. Cependant, des analyses ont montré que les individus ayant un faible statut socio-économique bénéficient davantage des politiques de prévention en termes de résultats de santé puisque ces individus ont une plus forte prévalence de facteurs de risque [START_REF] Sassi | Improving Lifestyles, Tackling Obesity: The Health and Economic Impact of Prevention Strategies[END_REF]. En outre, pour contrebalancer l effet gatif des ta es, des esu es edist i uti es peu e t t e ises e pla e.

Pa e e ple, les so es olle t es g â e au ta es pou aie t se i à fi a e des o s d a hat pou des p oduits sai s ou des pa ie s de f uits et l gu es à l i te tio des individus à bas revenus, d fa o a le e t affe t s pa l i t odu tio de telles ta es.

Social inequalities in health-related behaviours:

Summary/Résumé Is the grass greener on the other side? xxiii

Prolongements possibles de ce travail

Les analyses présentées dans cette thèse ouvrent de nouvelles pistes de recherche et soulèvent des questions qui pourraient être étudiées dans des investigations futures. Quatre pistes de recherche peuvent ainsi être proposées.

General Introduction

Social inequalities in health-related behaviours:

General Introduction Is the grass greener on the other side?

-2 -This thesis deals with social inequalities in health-related behaviours such as lifestyle risk factors for health (precisely, obesity and alcohol consumption) and the utilisation of health care services, in a number of OECD countries. This work relies on a micro-econometrics approach, using a range of national health survey data. This thesis aims to (a) compare social inequalities in health-related behaviours across countries with different settings; (b) shed light on the understanding of social disparities in health-related behaviours; and (c) examine how self-reporting may affect the rating of behavioural risk factors, and therefore affect the measurement of social inequalities. This general introduction is composed of four sections. Section 1 provides some background on health inequalities. Section 2 focuses on the determinants of health inequalities. Section 3 highlights the contribution of international comparisons. And, Section 4 presents the outline of this thesis.

Background

Disparities in health status (measured by mortality or morbidity) have been largely documented in the international literature in relation to gender, ethnicity, social background, education, socioeconomic status 1 , and geographical area (van Doorslaer et al., 1997; Mackenbach et al., 2008; OECD 2011). Studies on disparities in mortality and morbidity by socioeconomic status reveal that the worst-off die prematurely compared to the better-off, and that the poorest part of the population, the most vulnerable, are more affected by illness. Eurostat (2010) started to measure disparities in life expectancy by education level in European countries on a regular basis. The latest data shows that education-related gaps in life expectancy at age 30 vary from 2.5 years in women in Slovenia to 17 years in men in Estonia.

A number of studies aimed to understand health inequalities and to explore their determinants (Eurothine project; ECuity project; van [START_REF] Van Doorslaer | Explaining income-related inequalities in doctor utilisation in Europe[END_REF][START_REF] Cutler | Education and Health: Evaluating Theories and Evidence[END_REF]. Social inequalities in health-related behaviours:

General Introduction

Is the grass greener on the other side? -3 -Health inequalities are of major concerns for governments for two main reasons: they are unfair and they are source of social costs. First, health inequalities are unfair since they may occur from early childhood, and because everyone does not have the same opportunity for good health (Trannoy et al., 2010). Inequalities of opportunity linked to circumstances in childhood represent 46% of social inequalities in health (Jusot et al., 2013). Besides, these inequalities are avoidable given that better design of policy interventions may help reduce them (Woodward and Kawachi, 2000). Second, health inequalities may have broader societal impacts in terms of global welfare and labour market outcomes, poor health being associated with poor educational attainment and negative labour market outcomes. Mackenbach et al. (2011) estimate the monetary value of health inequality-related welfare losses at 9.4% of GDP. For these reasons, governments are increasingly paying attention to measuring and understanding health inequalities, in search of the most appropriate measures to tackle them.

The determinants of health inequalities

Health status is influenced by a variety of determinants: genetics2 , individual and contextual factors. Individual factors refer to social condition and individual choices, including living and working conditions, education level, socioeconomic status, integration in social life, health-related lifestyle behaviours (such as smoking, drinking, diet and physical activity), as well as the demand for health care services. Contextual factors refer to multiple surrounding dimensions, including national wealth, income inequality, health system features (e.g. supply of health care services, free access at point of care delivery, health prevention policy), social norms, and environment factors (e.g. transport and pollution).

All these determinants have an effect on health status, and interactions between them may influence health status more or less strongly. Understanding health inequalities relies heavily on the understanding of the relationships between socioeconomic factors, behaviours and health. The analysis framework of this thesis proposes to study social inequalities in behavioural risk factors and in health care utilisation as a means of addressing social inequalities in health. As shown below, this framework is consistent with G oss a s odel a d its e te sions. Grossman (1972[START_REF] Grossman | The Human Capital Model[END_REF] developed an economic framework for the demand for health based on the human capital theory. In this framework, health is a capital which depends on the initial stock and depreciates over time, but can be increased with investment in health. Individuals are active producers of their health, buying market inputs (e.g. health care, food) and combining them with their own time to increase their utility. Education increases efficiency in the production of health since more educated people are in a better position to process health information, and make better investment in health. G oss a s odel p o ides a theo eti al f a e o k fo aki g p edi tio s of health as a fu tio of education and socioeconomic status, which are positive determinants of the investments in health. Thus, G oss a s odel is a solid foundation for the study of inequality in health (Galama and van Kippersluis,

Theoretical framework

2013).

As investment in health is a key concept in this model, lifestyle behaviours and individual preferences play an important role in this theoretical framework. A number of studies confirm the impact of health-related behaviours on social inequalities in health (McGinnis and Foege, 1993;Contoyannis and Jones, 2004;Stringhini et al., 2010). However, unhealthy behaviours may not all contribute to determining health status to the same degree or in the same direction. While smoking contributes largely to the well-known gradient of social health inequalities, drinking behaviours may sometimes contrast.

Van Kippersluis and Galama (2013) study why the rich drink more but smoke less, and they propose a theory of health behaviours to explain why richer people engage more in moderate unhealthy behaviours and less in harmful behaviours 3 .

I G oss a s odel, edu atio a d so ioe o o i status a e o elated to health. This correlation has been widely validated in empirical studies. However, evidence for a causal relationship remains debated. The challenge is to identify whether the social gradient in health reflects a causal link from socioeconomic status to health, or a reverse causality from health to social outcomes. This question has been studied in the literature leading to mixed findings. Evidence goes in both directions, showing for example that health influences labour (Morris, 2007;Lundborg et al., 2010;Burton et al. 1998)

and labour

General Introduction Is the grass greener on the other side?

-5 -influences health status (Llena-Nozal, 2009;Robone et al. 2011). About the latter, the impact of labour on health status has been shown to be positive in some studies and negative in others, but a convergence in findings emerges, suggesting that the negative health impact of work is related to situations in which workers have essentially no control (no choice) over the amount of work they provide (Bassanini and Caroli, 2014).

When studying inequalities in health-related behaviours, one important dimension to consider is individual time preferences i.e. whether people value more short-term satisfaction rather than long-term consequences of their health behaviours. In particular, about health-related and addictive behaviours, individuals must often make the trade-off between immediate satisfaction of unhealthy goods consumption (e.g. food high in fat and sugar, tobacco, and alcohol) and future losses in health capital.

Economic models for addictive goods were originally introduced by Becker and Murphy (1988) with the rational addiction theory which assumes that the consumer is aware of the future consequences of addictive goods consumption and accounts for them when making consumption choices. This model relies on the idea that current preferences for addictive goods depend on past and anticipated consumption of that goods. The rational addiction theory finds support in empirical studies, in particular in relation to smoking (Chaloupka and Warner, 2000;Clark and Etilé, 2002).

Individual time preferences are correlated to education and socioeconomic status, with little evidence on the direction of causality. Individuals who discount the future less (i.e. who have a preference for future) invest more in education and engage more in healthy behaviours (Fuchs, 1982).

Similarly, less educated and poorer people discount the future more heavily than richer people (Becker and Mulligan, 1997). The interplay between time preferences, health behaviours, and education is therefore of importance for the study of social inequalities in health-related behaviours. Individual time preferences may affect the relationship between education and health by having a mediating role of social health inequalities, as suggested by empirical studies (van der Pol, 2011; Jusot and Khlat 2013).

Focus on social inequalities in health-related behaviours

Figure 1 illustrates the analysis framework of this thesis wherein social disparities in health outcomes results from direct and indirect pathways of social determinants. Tackling social inequalities in health can be achieved to some extent by addressing inequalities in behavioural risk factors and inequalities in health care utilisation. Differences in morbidity and mortality may be directly related to living and working conditions (e.g. type of occupation that may have inherent cancer risks), but they may also emerge from between-groups differences in behavioural risk factors (e.g. smoking, obesity, alcohol use) (arrow (a) in Figure 1) and differences in health care services utilisation (e.g. doctor consultations) (arrow (b)). Lifestyles and behavioural risk factors play an important role in the relationship between health and socioeconomic factors. They are often significantly influenced by education and socioeconomic status and, at the same time, they contribute to health and longevity by affecting the probability of developing a wide range of diseases (e.g. cardiovascular diseases, diabetes, cancers, musculoskeletal diseases, mental ill-health).

Similarly, access to health care is as important as lifestyle in the determination of social health inequalities. For example, higher-income people are shown to have better access to health care services, which translates into differences in health outcomes. Thus, reducing social health inequalities depends not only on efforts directly made to improve health outcomes of the worst-off, but also efforts to reduce social inequalities in behavioural risk factors and health care utilisation. In addition to health-related behaviours, external factors may interact with and exacerbate or diminish social inequalities in health. For instance, there are potential interactions with contextual and environmental factors, such as health system characteristics (e.g. density of medical General Introduction Is the grass greener on the other side? -7 -services, copayment system), social norms, transport and pollution. This aspect is further discussed in Chapter 4, with the analysis of health system characteristics as determinants of inequities in health care utilisation.

How can international comparisons contribute?

The importance of cross-country comparisons

This research focuses on measuring and comparing social inequalities in health-related behaviours with the aim of making the best use of multi-country analysis. International studies (either qualitative or quantitative, sharing country experiences or making cross-country comparisons) allow policy makers to learn from other countries about good practices and to understand the impact of policies, although they do not go without difficulties.

International studies can help countries develop their knowledge and understanding, and they favour the introspection, enabling change in the way of thinking and identifying problems. Cross-national evaluations enable to draw an accurate picture of the situation, to identify where problems are, how other countries deal with it, and which countries perform better, how and why. International comparisons also provide a basis for exploring the relationships between country performance and policy setting, and more specifically, they offer a source of knowledge and evidence for better understanding of the impact of public policies. However, such cross-national research is not without difficulties. Conceptual and practical problems often emerge when undertaking international comparisons, including issues in availability and comparability of data, discrepancies in national settings and institutional features. This thesis focuses on the analytical and methodological aspects of cross-country evaluation rather than policy comparisons. This work does not intend to review national policies in place or to propose a set of good practices. Instead, it aims at drawing an accurate picture of inequalities across countries, collecting national survey data, making data comparable, and developing comparable measures. Also, this thesis raises methodological issues and questions around the interpretation of results for the best use of policy recommendations.

General Introduction

Is the grass greener on the other side? -8 -

Cross-country studies on inequalities in health

There are two initiatives at the European level, initiated in the 1990s, which aim to measure and understand inequalities in health (Jusot, 2010). Funded by the European Commission, these two projects highlight the existence of health inequalities, and the great variation in health inequalities across countries, but they also study inequalities in health-related lifestyle behaviours and inequalities in access to health care.

First, the EU Working Group on Socioeconomic Inequalities in Health, followed by the collaborative research programme Eurothine (Tackling Health Inequality in Europe) led by Johan Mackenbach and Anton Kunst, showed that health inequalities were substantial throughout the European Union in the 1990s, and that important variations in the magnitude of health inequalities exist between countries, suggesting scope for reducing health inequalities. More recently, the subsequent and related European project EURO-GBD-SE has identified the most important entry-points for policies aimed at reducing health inequalities (Eurothine project).

Second, the ECuity project was initiated in the early 1990s, and led by Eddy van Doorslaer, Adam Wagstaff and Andrew Jones. Overall, the project brought significant methodological breakthroughs and important new results focussing on the following areas: inequity in health care financing, inequity in health care delivery, inequity in health care utilisation, and inequalities in health status. The current ECuity III project extends the analysis to determinants of health care demand (e.g. income inequality, private health insurance, user charges) and the causal relationships to inform policy makers (ECuity project).

An extension of this work was the OECD Equity project with the objective to cover a larger set of countries [START_REF] Van Doorslaer | Income-related Inequality in the Use of Medical Care in 21 OECD Countries[END_REF]). This research focussed on inequity in health care utilisation by income level, and encompassed 21 OECD countries (a number of European countries, as well as Australia, Canada, Mexico, USA). This project highlighted pro-poor inequities in general practitioners (GP) visits and pro-rich inequities in doctor and specialist visits in a number of countries.

It is important to recognise that these projects could not exist without efforts to develop harmonised health survey data at the European level (e.g. European Community Household Panel, European Health Interview Survey, Survey of Health And Retirement in Europe). As governments pay more attention to health inequalities, technical efforts are continuously made at the international level to monitor and understand these inequalities. For instance, the regular monitoring of health inequalities at Eurostat now includes the new measure of differences in life expectancy by education level.

These two important programmes of work on the measurement and understanding of health inequalities and possible ways of tackling them open new ways of research. In particular, more research may be needed to extend country coverage to non-European countries. In addition, the field of statistics and econometrics sees continuous methodological developments, and new techniques may help to improve previous research. For instance, new developments of the measurement of inequalities enable an improved assessment of cross-country comparison. In particular, when analysing social inequalities in health from an international perspective, it is essential to use appropriate methods to compare inequalities between countries with different settings (e.g. structure of the population, distribution of education level and social class). Aggregate measures of inequalities have been used to overcome this problem. These include the concentration index, the relative and absolute index of inequality, and other recent improvements of these indexes. Further methodological discussion is presented in Chapter 1, and an empirical application is shown in Chapter 2, with the analysis of social inequalities in obesity and overweight in a selection of OECD countries.

Cross-country studies on inequalities in health-related behaviours

An additional motivation for the topic of this thesis comes from the need for better knowledge of the scope of inequalities in health-related behaviours in a multi-country context, in order to consider and design operable policy instruments oriented towards lifestyle behaviours. Evidence on social disparities in health-related behaviours from an international perspective has to date been poorly informed. Although social inequalities in health have been widely examined for a number of health outcomes, studies have not focused so much on behavioural risk factors. One of the main reasons for this is that health-related behaviours are difficult to measure, suffering from inconsistency and self-reporting bias. For instance, measures of Body Mass Index 4 and obesity may be subject to inaccuracy due to misreported height and weight. Similarly, measures of drinking suffer from self-report bias with strong underreporting of alcohol consumption. Nevertheless, the literature shows a growing number of international studies looking at social disparities in obesity (Mackenbach et al., 2008;[START_REF] Costa-Font | Income inequalities in unhealthy lifestyles in England and Spain[END_REF], in diet and physical activity (Gordon-Larsen et al., 2006;Filippidis et al., 2014), in smoking (Cavelaars et al., 2000;Mackenbach et al., 2008), although less is known about disparities in alcohol consumption.

Social inequalities in health-related behaviours:

General Introduction

Is the grass greener on the other side? -10 -In addition, the issue of self-reporting raises the question of whether the self-report bias affects the rating of individual behaviours, and if so, whether the self-report bias varies by socioeconomic group and affects the measurement of social inequalities. There is a small number of studies looking at the selfreport bias and disparities in obesity (Cawley, 2000;Lakdawalla and Philipson, 2002;Ljungvall et al. 2012;[START_REF] Costa-Font | Income inequalities in unhealthy lifestyles in England and Spain[END_REF]). In particular, Ljungvall et al. (2012) found evidence on Swedish data that social disparities in obesity are affected by self-report bias in women, but not in men. [START_REF] Costa-Font | Income inequalities in unhealthy lifestyles in England and Spain[END_REF] corroborate this finding since they found on Spanish data that (absolute) inequalities in obesity are stronger after correction for self-report bias, especially in women. However, to our knowledge there is no research on the effect of the self-report bias on social disparities in alcohol consumption. This point is further explored in Chapter 3.

The study of access to health care and demand for care complements the analysis of inequality in behavioural risk factors. The previous section showed that inequalities in morbidity and mortality can be the results of prior inequalities in behavioural risk factors and health care utilisation. Previous studies around the year 2000 have shown that in numerous countries higher-income people compared to lowerincome people are more likely to visit doctors, in particular specialists and dentists, and to take up cancer screening, this being true for the same level of needs for health care 5 (van Doorslaer and Masseria, 2004; Or et al., ; Bago d U a et al., 2009). Since 2000, countries have put in place reforms that may have influence access to care (e.g. gatekeeping system, increase/reduction in copayment, cancer screening programme). Hence, there is a need to re-assess inequities in health care utilisation and to analyse these inequities in the light of the health system characteristics. In particular, in order to best inform policy makers, it will be relevant to identify which health system features characterise countries with a lower degree of inequities. This point is explored in Chapter 4. -11 -policy implications of social inequalities in health-related behaviours. Research questions explored through this thesis are three-fold and can be summarised as follows:

What does this thesis bring?

 How can we compare social inequalities in health across countries with different settings (e.g. structure of the population, distribution of education level and socioeconomic status)?

 Beyond the observation and monitoring of social disparities in health, how can we shed light on the understanding of these disparities? And, how can we best inform policy decision makers?

 How does self-reporting affect the rating of behavioural risk factors? Does self-report bias vary by social group and therefore affect the measurement of social inequalities?

Outline of this thesis

This thesis deals with social inequalities in behavioural risk factors and utilisation of health care services in a number of OECD countries. The following chapters focus on two behavioural risk factors for chronic diseases: obesity and alcohol consumption. Utilisation of health care services is assessed through examining doctor visits (both GP and specialist), dentist visits, and breast and cervical cancer screening. This thesis relies on a micro-econometrics approach, using data from a number of national health surveys.

Chapter 1 presents the data and methods used in the different pieces of this work. National health survey data from 23 OECD countries were collected. Measures of obesity and alcohol consumption are described and their validity is questioned. In particular, the impact of self-reported outcomes on assessing inequality is questioned. Methods used to assess inequalities such as relative and absolute indices of inequality and concentration indices are presented in this chapter.

Chapter 2 deals with social inequalities in obesity and overweight in a number of OECD countries. This chapter consists of two articles. The first article, co-authored with Franco Sassi, was published in The European Journal of Public Health in 2013, and the second article, co-authored with Franco Sassi, Jody Church, Michele Cecchini and Francesca Borgonovi, was published in the OECD Economics Journal in 2011. Inequalities in obesity and overweight by education level and by socioeconomic status (SES) are examined using data from national health surveys of 11 countries. The size of inequalities was assessed on the basis of absolute and relative inequality indexes. Large and persistent social inequalities in obesity and overweight by education level and socio-economic status exist in OECD countries. These are consistently larger in women than in men. Absolute inequalities were largest in Hungary and Spain across the education spectrum. Relative inequalities were largest in France and Sweden with poorly educated men more likely to be obese (and respectively, in Spain and Korea for women).

In addition, a range of analyses conducted for Australia, Canada, France, England and Korea, were undertaken with the aim of exploring the relationship between education and obesity. The findings of these analyses show a broadly linear relationship between the number of years spent in full-time education and the probability of obesity, suggesting that increasing education at any point along that spectrum would be expected to reduce obesity to a similar degree, if the causal link between education and obesity had been established. Causality between education and obesity has not yet been proven with certainty, although evidence from France suggests that the direction of causality appears to run mostly from education to obesity. Moreover, most of the effect of education on obesity is direct. Last, further analyses show not only an absolute effect of the education level on obesity, but also a relative effect, i.e. the i di idual s edu atio le el relative to the pee s edu atio level has an influence on obesity.

Chapter 3 focuses on disparities in alcohol consumption across education levels and socioeconomic groups. This study, co-authored with Franco Sassi, is currently under review in the European Journal of Public Health. The analysis covers 13 countries and aims to identify which population groups most often engage in hazardous drinking and it assesses how self-report bias may affect social inequalities in drinking. Results show that socioeconomic disparities in hazardous drinking are intertwined with gender differences. More educated women are more likely than less educated women to engage in hazardous drinking, while the opposite is observed in men in most countries. Large discrepancies in alcohol consumption between survey-based and aggregate consumption estimates were found. Correcting for self-report bias increased estimates of social disparities in women, and decreased them in men, to the point that gradients were reversed in several countries (from higher rates in less educated/SES men to an opposite pattern). While acknowledging the limitations of the approach used for correction, this study provides evidence of a likely mis-estimation of social disparities in alcohol consumption, in both men and women, due to self-report bias in surveys of alcohol consumption. Correcting for self-report bias leads to a relatively larger increase in hazardous drinking rates in higher educated/SES people. This study contributes to a better knowledge of the social dimensions of alcohol drinking and can therefore help in the targeting of alcohol policies.

General Introduction

Is the grass greener on the other side? -13 -Chapter 4 investigates inequalities in the utilisation of medical services. This chapter was published in The European Journal of Health Economics in 2013. Income-related inequalities and inequities in health care service utilisation are assessed in 18 countries by the means of concentration indices. The analysis focuses on doctor and dentist visits, and breast and cervical cancer screening. In most countries, for the same health care needs, people with higher incomes are more likely to consult a doctor than those with lower incomes. Pro-rich inequalities in dental visits and cancer screening uptake are also found in nearly all countries, although the magnitude of these varies among countries. Part of the cross-country discrepancies can be explained by the differences in health system characteristics. In particular, larger inequities are found in countries where: universal health coverage is not achieved, health care financing relies on a large share of private insurance and out-of-pocket payments, GPs do not act as gatekeepers, health care provision is mostly private and national cost-sharing arrangements do not include free care at the point of delivery.

Finally, a general conclusion provides a discussion of the main findings in the light of the objectives of this thesis, and opens up discussion around methodological considerations and policy recommendations that can be drawn. Chapter 1.

Data and methods

DATA

This section consists of three parts. First the data are described, then data comparability and construction of variables are discussed, and finally, the data limitations are presented.

Data sources

Data sources for this work rely on national health interview surveys. Health interview surveys generally collect information from individuals on socio-demographic characteristics, living and working conditions, perceived and objective health status (e.g. acute and chronic diseases), health-related behaviours (e.g. smoking, drinking, physical activity, diet), and their utilisation of health services (e.g.

doctor consultation, preventive screening).

Data were gathered from national health and lifestyle surveys for 23 high-income countries:

Australia, Austria, Belgium, Canada, Czech Republic, Estonia, Finland, France, Germany, Hungary, Ireland, Italy, Japan, Korea, New Zealand, Poland, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, United Kingdom (England), and USA. However, all of these countries are not included in the four papers due to data availability and limitations in areas covered by the surveys. Table 1 lists the national health surveys used in the different pieces of work, and the national institutions supplying the data.

All analyses presented in this thesis use the sampling weights provided with the data.

Data comparability and construction of variables

Although the use of different national surveys may be a source of data heterogeneity across countries, all the variables derived for our analyses were constructed in order to get the highest level of comparability across countries. This section discusses the construction of the dependent and independent variables used in the four papers. The dependent variables are related to: (i) obesity and overweight, (ii) risky alcohol consumption, and (iii) health care services utilisation.

Obesity and overweight

The Body Mass Index (BMI) is a measure of weight-for-height that enables to identify overweight and obesity status. It is equal to the weight (in kg) divided by the height (in meter squared). The same BMI thresholds were used in all countries to define overweight (BMI of 25 and over) and obesity (BMI of 30 and over), although there are suggestions that lower thresholds should be used in Asian populations (WHO, 2004). Building cross-country comparable measures of obesity and overweight is then straightforward although some caution should be taken due to discrepancies in self-reported and measured data on height and weight (see discussion in 1.3. Data limitations).

Risky alcohol consumption

International comparisons in alcohol consumption need to rely on a common measure of alcohol level. Each country establishes its own national guidelines for the definition of a standard drink (how much pure alcohol is contained) and recommendation for harmful drinking limits (defined as number of glasses or amount of pure alcohol per week). No international consensus in drinking guidelines currently exists [START_REF] Furtwaengler | Lack of consensus in low-risk drinking guidelines[END_REF]. Despite this limitation, comparable drinking outcome measures were derived using information on individual quantity and frequency of drinking provided in national health surveys. The outcome measures include:

 Drinking status, indicating whether people drank any alcohol or were abstainers in the past 12 months.



Hazardous drinking, corresponding, in this study, to a weekly amount of pure alcohol of 140 grams or more for women, and 210 grams or more for men. This measure refers to the limits above which people are at risk for their health. These thresholds correspond with the national Social inequalities in health-related behaviours:

Chapter 1 Is the grass greener on the other side? -23 -recommendations used in most countries (2 drinks per day for women and 3 drinks for men) although they differ slightly from those used by the WHO6 (Rehm et al., 2004). Republic, France, Hungary, Ireland, Italy, New Zealand, Slovak Republic, and Slovenia; 7 drinks for men and 5 drinks for women in Australia; and 8 drinks for men and 6 drinks for women in Switzerland). Our analyses focused on regular HED, i.e. at least one episode per week.

Health care services utilisation

Regarding health care services utilisation, the analysis focuses on visits to (i) doctors (in most countries further information on separate GP and specialist visits are available); (ii) dentists; and (iii)

Independent variables

National health surveys provide socio-demographic information on adults such as gender, age, ethnicity, marital status, working status, education level, and socioeconomic status (occupation-based or income level). Ethnicity is provided in few countries, namely, New Zealand (European / Maori / Pacific people / Asian and others), the UK (White / Black / Indian, Pakistani, and Bangladeshi / Others), and the US (Non-Hispanic White / Non-Hispanic Black / Mexican American / Others). For the purpose of the analyses, marital status is categorized into Married / Single / Other (divorced, separated, widow).

Working status is defined as Working / Not working.

Measures of education level and socioeconomic status

International standard classifications, such as International Standard Classification of Education (ISCED) and International Standard Classification of Occupation (ISCO), were used to define education level and socioeconomic status (SES), reducing limitations from data heterogeneity. Education level is recoded into three groups: low (ISCED 0, 1, 2) / medium (ISCED 3, 4) / high (ISCED 5,6), which broadly correspond to primary, secondary, and tertiary education.

An attempt was made to standardise different occupation-based socioeconomic status, by recoding professions as: lowest (unskilled manual) / middle-low (semi-skilled manual) / middle (skilled manual, non-manual) / middle-high (managerial technical) / highest (professional). A five-level occupation-based socioeconomic status variable was available or could be derived in England, France, Hungary, Italy, Japan, Spain, Sweden and Switzerland. In countries for which an occupation-based social class variable could not be derived, household income was instead used as an indicator of socioeconomic status (Australia, Austria, Belgium, Canada, Czech Republic, Estonia, Finland, Germany, Ireland, Korea, New Zealand, Poland, Slovak Republic, Slovenia, and the US). As much as possible, the equivalised household income was used accounting for the size and composition of households as permitted with the OECD-modified equivalence scale (Hagenaars et al., 1994). Further details on data comparability are available upon request.

Data limitations

Despite the variety of data sources available, the choice of health surveys used in this work was mainly driven by data availability and comparability criteria. This section first presents and discusses data limitations, and then focuses on issues with self-reporting and the possible correction procedures to overcome this problem.

National and international data sources

Researchers who aim to undertake cross-country comparisons generally face dual problems of availability and comparability of data at the international level. In particular, for the four studies presented in this thesis, one of the major difficulties was to find adequate data sources, due primarily to the small number of surveys on health and lifestyle behaviours conducted at the international scale, and secondly, because survey data gathered from multiple national sources suffer from heterogeneity from survey design and sampling and inconsistency in survey questionnaires.

Social inequalities in health-related behaviours:

Chapter 1 Is the grass greener on the other side? -25 -Several international surveys were identified but found unsuitable for our analyses.



The



The European Union Statistics on Income and Living Conditions (EU-SILC) is an instrument aimed at collecting timely cross-sectional and longitudinal multidimensional micro-data on income, poverty, social exclusion and living conditions. Although the EU-SILC contains some information on health, it is not convenient for the analyses presented in this dissertation as it does not cover healthrelated lifestyles and health care utilisation.



The European Health Interview Survey (EHIS) consists of four modules of questions on health status, health care use, health determinants, and background variables. These modules may be implemented at a national level either as one specific survey or as elements of existing surveys (i.e.

existing national health interview surveys or other household surveys). The first wave of the EHIS was implemented across countries between 2006 and 2009; the second wave is currently on the field. Due to limited data availability, EHIS data was not used for the studies which required trends analyses. However, EHIS was used for the analysis of health care services utilisation.

Some conclusions can be drawn from the data collection experience. Collection and harmonization of micro-data required a major work. Several months were necessary to identify and obtain the microdata for the 23 aforementioned countries. This work required investigation of numerous national sources of micro-data, selection of data appropriate for the purpose of the analyses, communication with counterparts in the national institutes, and preparation of the legal agreements in order to access the Social inequalities in health-related behaviours:

Chapter 1 Is the grass greener on the other side?

-26 -micro-data files. Given the challenges of data collection and harmonization, the choice of the countries included was mostly guided by data availability. Once the data files were received, significant effort was made to process and harmonize the data, in order to create comparable variables across countries (e.g. cleaning micro-data files and constructing a set of harmonized variables across countries).

Collecting data from different national sources creates a source of data heterogeneity due to survey sampling and survey methods that may differ across countries (e.g. face to face interview, Computer-Assisted Personal Interview technology). This problem could have been minimised if one single international or European survey data source was used, although these surveys are often limited in the richness of data as described above.

The data collection experience revealed some difficulties to get access to data files depending on countries. The UK and the US deliver survey data very timely and easily (e.g. without long process for data use agreement). Timeliness is an important criterion for research purposes; however, it is common to see survey data released two or more years late because of data cleaning and long anonymisation procedures.

Finally, efforts made by international organisations (Eurostat, OECD, WHO) to collect, prepare and distribute comparable health data should be acknowledged. Although international survey data are extremely valuable for research and policy decision making, international initiatives like the EHIS may struggle to expand because of issues related to costs, government priorities, and technical difficulties. For instance, one can observe how difficult it is to find an international consensus on the definition of a harmonised health question module.

Self-report bias: description and impact on measuring inequalities

A key challenge of health survey data is the self-report bias issue that may arise when people provide self-assessed health outcomes and anthropometric measures in surveys. Self-report bias is identified as a systematic error (under-or over-estimation) of health outcomes by certain population groups compared to others. Self-report bias in self-assessed health has been identified in a number of countries (Lindeboom and van Doorslaer, 2004;Jürges, 2007;Hernández-Quevedo et al., 2008;Pfarr et al., 2012). In our work, the self-report bias issue may arise as presented below.

Obesity

Concerning obesity and overweight, most national health surveys collect self-reported height and weight which tend to underestimate BMI. Only a few health surveys (e.g. the Health Survey for England, the Korean KNHANES, and the US NHANES) provide height and weight measured by clinical examination. This difference in data has a significant impact on the level of obesity and overweight, but to a lesser extent on social inequality. Indeed, the use of self-reported data may potentially bias results, as a number of people tend to report incorrectly their height and weight. However, to our knowledge, there is no clear evidence that self-report bias may vary among individuals with different levels of education or socioeconomic status.

Alcohol consumption

Regarding alcohol consumption, sales data are often regarded as more accurate than health surveys although they have their own limitations. The WHO produces estimates of adult per capita alcohol consumption (APC) based on data from the Global Information System on Alcohol and Health (WHO, 2014), which in turn draws upon various data sources including sales, tax, international trade, and survey data. The APC estimates cover recorded and unrecorded alcohol consumption. The latter refers to homemade or illegally produced alcohol, smuggled alcohol, alcohol for industrial and medical use, alcohol obtained through cross-border shopping, and alcohol consumed by tourists. The unrecorded alcohol consumption accounts for nearly 30% of total worldwide adult consumption. These aggregate APC estimates provide the most reliable information to determine broad national trends and draw country profiles of alcohol consumption.

However, their aggregate nature does not allow identification and examination of individual patterns of drinking. To design appropriate policies, it is desirable to understand how harmful forms of drinking have evolved over time, and to identify which population groups are most likely to engage in harmful drinking. Such analyses help policy makers to target population groups to develop strategies to reduce harmful drinking. Population health and lifestyle survey data providing information on alcohol consumption and individual characteristics are best suited for assessing drinking behaviours across different population sub-groups, although these surveys suffer from important limitations.

Limitations of survey-based data on alcohol consumption are due to measurement bias including underreporting by surveyed respondents and selection bias in survey sampling. Drinking levels reported in surveys have been shown to account for only 40-60% of alcohol sales [START_REF] Midanik | The Validity of Self-Reported Alcohol Consumption and Alcohol Problems: A Literature Review[END_REF]WHO, 2011). A Social inequalities in health-related behaviours:

Chapter 1 Is the grass greener on the other side? -28 -major determinant of such discrepancy is underreporting in surveys [START_REF] Ely | Methods of estimating individual levels of alcohol consumption in the general population[END_REF][START_REF] Stockwell | Under-reporting of alcohol consumption in household surveys: A comparison of quantity-frequency, graduated-frequency, and recent recall[END_REF][START_REF] Rehm | Statistical modeling of volume of alcohol exposure for epidemiological studies of population health: the US example[END_REF][START_REF] Boniface | How is alcohol consumption affected if we account for underreporting? A hypothetical scenario[END_REF][START_REF] Meier | Adjusting for unrecorded consumption in survey and per capita sales data: Quantification of impact on gender-and age-specific alcohol-attributable fractions for oral and pharyngeal cancers in Great Britain[END_REF]. For instance, the Health Survey for England in 2002 provides an estimate of 5.8 litres of pure alcohol per capita (population aged whereas the WHO estimates recorded adult (15+ years) per capita consumption for the UK as 11 litres 8 . Canada are 3 and8.2 litres, andfor the United States 3.6 and8.7 litres. Another limitation of survey data is a possible measurement error due to the under-sampling of certain groups. In particular, household-based surveys may under-sample groups of people with high alcohol consumption (e.g. students, alcohol dependent people) and may not include at all groups that are most at risk of harmful drinking (e.g., homeless, people in institutions) [START_REF] Stockwell | Under-reporting of alcohol consumption in household surveys: A comparison of quantity-frequency, graduated-frequency, and recent recall[END_REF][START_REF] Meier | Adjusting for unrecorded consumption in survey and per capita sales data: Quantification of impact on gender-and age-specific alcohol-attributable fractions for oral and pharyngeal cancers in Great Britain[END_REF].

The corresponding figures for

One more source of bias in survey data is the assumed size and strength of a standard drink. Although many national surveys offer a reminder 9 of the definition of how much pure alcohol is contained in a standard drink, the reported number of standard drinks consumed may differ greatly for different respondents.

Health care services utilisation

Regarding the annual use of health care services, administrative data from health registries or reimbursement files would be more accurate than survey-based data. However, these registries data are difficult (if not impossible) to access due to confidentiality issues and researchers have no other choice than to rely on survey data.

The self-report bias in the literature

Evidence for differences in self-assessed obesity and alcohol use by population group (e.g. gender, ethnicity, education level, social class) is fairly scarce. Cawley (2000) and Lakdawalla and Philipson (2002) analysed the self-report bias in weight in the US (see Box A for example). The underestimation of weight appears to be consistent among women, and larger in heavier men compared to lighter men (Lakdawalla and Philipson, 2002). Concerning alcohol consumption, some research show that underreporting and non-response bias are stronger among heavy drinkers (Townshend & Dukat, 2002;Lemmens et al., 1988;Zhao et al., 2009, Studer et al., 2013). 8 Some of this discrepancy may be due to higher levels of alcohol consumption in other UK countries.

Social inequalities in health-related behaviours:

Chapter 1 Is the grass greener on the other side? -29 -

BOX A:

Correcting BMI measure for self-report bias Some studies focused on how to correct BMI data from self-report biases. In particular, Cawley (2000) proposed to correct the self-reported NHIS US data from the self-report bias using the measured data on height and weight from the NHANES. The NHANES contain both self-reported and measured height and weight. In order to gauge the self-report bias, we regress the self-reported BMI and its square on the actual BMI by gender and ethnicity. The R-squared is high, indicating that the quadratic function fits the data quite well. Figure A1 shows the size of the self-report bias by gender and ethnicity. BMI is underestimated by obese people (BMI>30) and particularly by Mexican-American men and women. On the contrary, non-Hispanic Black men tend to overestimate their BMI. The coefficient estimates obtained from the previous regression are then applied to correct the self-reported BMI in NHIS data. This correction procedure leads to the same results in terms of the value of regression-based estimates and the strength of correlations with the determinants of inequalities, but the rates of obesity and overweight are higher.

Self-reported BMI

Non-Hispanic White Men

Non-Hispanic Black Men Mexican American Men Non-Hispanic White Women Non-Hispanic Black Women Mexican American Women Social inequalities in health-related behaviours:

Chapter 1 Is the grass greener on the other side? -30 -However, few studies investigate the effect of the self-report bias on social inequalities in healthrelated behaviours. So far, it has been suggested that the self-report bias in obesity does not significantly affect social inequalities (Sassi et al., 2009 for USA;Costa-Font et al., 2014 for Spain). However, if differences in self-reported measures (e.g. weight, height, number of drinks consumed) were to exist across social groups, then we would expect a significant effect on inequalities. For instance, evidence shows that lower-educated people are more likely than higher-educated people to be obese. If the former (or latter) were more prone to underestimate their weight, then education-related inequalities in obesity would be underestimated (or likewise overestimated). To our knowledge, there is no evidence in the literature on self-report bias in obesity or alcohol use by socioeconomic background. However this thesis provides preliminary evidence that suggests a significant impact of self-report bias on social inequalities in hazardous drinking. The methodology used to correct for self-report bias in alcohol consumption is described in Box B.

BOX B: Correcting alcohol consumption from underreporting bias

Several studies propose some attempts to correct the underreporting bias in alcohol survey data.

The most recent approach published by Rehm and colleagues is based on the triangulation of survey data with recorded aggregated per capita consumption data by modelling the upshifted distribution of alcohol consumption [START_REF] Rehm | Statistical modeling of volume of alcohol exposure for epidemiological studies of population health: the US example[END_REF]. This correction procedure leads to sizeable change. For instance, this method applied on Canadian data allows the assessment of the magnitude of change in the proportion of hazardous drinkers: the rate of male hazardous drinkers (i.e. who drink more than 30g of pure alcohol daily) would increase from 12% (survey-based) to 32% (after correction) (and respectively from 7% to 21% for female). Figure B1 illustrates the shift of the distribution of alcohol consumption.

However, this method uniformly up-shifts the entire distribution of alcohol consumption, although some evidence suggests that the underreporting bias is not evenly distributed and may be larger in hazardous drinkers (Townshend and Dukat, 2002;Lemmens et al., 1988). The lack of an objective measure of alcohol consumption in health surveys prevents an accurate assessment of the size of the self-report bias in different individuals and population sub-groups, which has been possible, in the case of BMI measurement as described above.

Social inequalities in health-related behaviours:

METHODS

Analytical approaches used in this work consist of regression-based models and a variety of inequality measures. This section describes the methodology employed to assess inequalities within and across countries.

Multivariate logistic regression

Multivariate logistic regression analyses were undertaken to assess the link between the studied health outcome and the socioeconomic dimension (either education attainment or socioeconomic status) by adjusting for a range of usual covariates (e.g. age, gender, marital status, ethnicity (when available), smoking status, and occupation status). These variables are further described above in the Data section in this chapter. The advantage of the logistic model lies in providing odds ratios that are easily interpretable as the odds of an event occurring in one group (e.g. the highest socioeconomic group) compared to the odds of it occurring in another group (e.g. the lowest socioeconomic group).

Regression analyses were performed for men and women separately in three of the four studies. In the studies on obesity and alcohol consumption, patterns by education level and SES vary across gender. Regression models were thus devised for men and women separately (either by performing two separate models or by including gender-education and gender-SES interactions). On the other hand, in the study of health care services utilisation, pooling men and women in the same model with adjustment for gender supposes that the utilisation of health care services only changes by one coefficient between men and women, and that the patterns by SES do not differ between genders.

The use of logistic regressions provides an accurate picture of inequalities within countries.

However that approach is less useful in comparisons across countries, and over time, because of differences in the size and nature of socioeconomic groups in different countries and time periods. The use of indices of inequalities permits to overcome, at least in part, the problems just described.

There is a vast literature on the indices of inequalities [START_REF] Pamuk | Social Class and Inequality in Mortality from 1921 to 1972 in England and Wales[END_REF][START_REF] Wagstaff | On the Measurement of Inequalities in Health[END_REF]Mackenbach et al., ;O Do ell et al., 2008). In this work, health inequalities related to education level and socioeconomic status are assessed using either the relative and absolute indices of inequality, or the concentration index. The following section presents these different measures.

Relative and absolute index of inequality

The relative index of inequality (RII) is used to compare the size of health inequalities across countries along two dimensions: education level and socioeconomic status. The RII has been largely employed to analyse socioeconomic inequalities in health across different regions (Mackenbach et al., 2008). The RII is the ratio between the rate of the studied health outcome (e.g. good health) among persons in the bottom socioeconomic group (rank 0) and those in the top group (rank 1) [START_REF] Pamuk | Social Class and Inequality in Mortality from 1921 to 1972 in England and Wales[END_REF][START_REF] Mackenbach | Measuring the Magnitude of Socio-Economic Inequalities in Health: an Overview of Available Measures Illustrated with Two Examples from Europe[END_REF].

For grouped data, the RII is obtained by fitting a regression line for the relationship between the health out o e ate fo a pa ti ula g oup a d that g oup s elati e positio i the so ial hie a h as shown in Figure 1. It takes into account the population size and the relative socioeconomic position of the groups, assuming that the socioeconomic groups are ranked in a hierarchical way. For regressions on grouped data, it is more efficient to use Weighted Least Squares estimators to avoid heteroskedasticity of the error term [START_REF] Wagstaff | On the Measurement of Inequalities in Health[END_REF]. This implies that the regression equation is transformed as follows:

√ √ √
where Y j is the health outcome of the class j, n j is the size of the class j, X j the relative rank of persons in class j, and u j the error term. The slope index of inequality (SII), also called the absolute index of inequality (AII), is derived from the relative index of inequality as a means of gauging the absolute size of inequalities in different countries. The SII is equal to the slope of the above mentioned regression line, and it also corresponds to the difference between the rate for the worst off in the bottom socioeconomic group (rank 0) and the rate for the best off in the top group (rank 1). The SII can be interpreted as the absolute effect on rates in moving from the lowest to the highest ends of the socioeconomic scale.

In the case of negative health outcomes (e.g. being obese), we rank individuals from the highest to the lowest socioeconomic position, so that the RII and SII can be equally derived. -34 -health doubles 10 , the relative inequality will remain unchanged but the absolute inequality will double. On the other hand, the SII depends on the difference in health outcomes in the population and is sensitive to the mean value of the health outcomes of the population [START_REF] Wagstaff | On the Measurement of Inequalities in Health[END_REF]. Though, the SII is invariant to uniform change, i.e. an increase of 10% in the health outcome in all the socioeconomic groups will leave the absolute index unchanged. In summary, the absolute and relative indices of inequality may vary in opposite ways and so it is important to present both indicators.

Concentration Index

The concentration index (CI) is defined as referenced to the concentration curve, which graphs on the x-axis the cumulative percentage of the sample ranked by wealth beginning with the poorest and on the y-axis the cumulative percentage of the health variable corresponding to each cumulative percentage of the dist i utio of the ealth a ia le O Do ell et al., 2008). Figure 2 illustrates the concentration curve.

Figure 2. Example of a concentration curve

If the health variable is evenly distributed along the social dimension, the concentration curve coincides with the diagonal (or the line of equality). If good health outcomes are more concentrated among high-income people, then the concentration curve will fall below the line of equality. Conversely if 10 -35 -good health outcomes are more concentrated among low-income people, the concentration curve is above the diagonal. The farther the concentration curve is from the diagonal, the higher the degree of inequality.

The CI is defined as twice the area between the concentration curve and the equality line, and thus it is bounded between -1 and 1, with the sign indicating the direction of inequality -a positive index indicates pro-rich inequality, a zero value indicates no inequality, and a negative index indicates pro-poor inequality.

The CI of a variable Y a e o puted usi g a si ple o e ie t o a ia e fo ula: [1] where μ is the weighted sample mean of Y, cov w denotes the weighted covariance and Ri is the relative fractional rank of the ith individual in the social distribution. Another option to obtain robust estimates fo CI a d its sta da d e o o sists i u i g the follo i g o e ie t eg essio of the t a sfo ed Y on relative fractional rank: [2] where σ r 2 is the variance of Ri and β 1 is equal to CI, and the estimated standard error of β 1 provides the estimated standard error of CI.

In the case of binary health outcomes, the CI does not satisfy two desirable properties: (a) the range of the index does not vary with the mean of the health outcome Y, and (b) the ranking of countries a ies depe di g o hethe the good att i ute is oded o i o p ope t . To sol e these issues, Wagstaff (2005) and Erreygers (2009) proposed to normalise the CI to take into account the bounded nature of the binary outcome. The Erreygers index (E) and the Wagstaff index (W) are defined for a binary outcome as follows:

[3]

[4] he e μ is the ea of the health out o e.

Social inequalities in health-related behaviours:

Chapter 1 Is the grass greener on the other side? -36 -Both E and W indices satisfy the two above mentioned properties. Wagstaff (2011) underlines that the non-normalised CI captures relative inequality, E measures absolute inequality, while W has no dimension. And, it is worth noting that the three measures (CI, E, and W) may lead to different results in terms of size of inequality and countries ranking. [START_REF] Wagstaff | On the Measurement of Inequalities in Health[END_REF] have reviewed and compared a range of inequality measures and have highlighted that one of the main advantages of the RII, AII and CI over other inequality measures (e.g. the range, the ratio of the two extremes) is that they capture the socioeconomic dimension of health inequalities by using information from the whole income distribution rather than just the extremes. In addition, these indices offer the advantage that they are statistically comparable across time periods and geographic regions.

Discussion of the measures used: pros and cons

On one hand, one advantage specific to the CI is that this index can be decomposed into the contributions of individual factors to social health inequality, this decomposition allowing the explanation of social inequalities in health.

On the other hand, one advantage of the RII and SII is that they are relatively easy to interpret. In contrast, interpreting the CI value is not as intuitive as for the RII and the SII. Although the concentration curves help visualise the results, the value of the CI in itself is somewhat meaningless. Koolman and van Doorslaer (2004) have shown that multiplying the CI value by a fixed coefficient (they estimated at 3/4) gives the proportion of the health variable that would need to be linearly redistributed from the richer half to the poorer half of the population (assuming that health inequality favours the rich) to arrive at equity. However these indices also present some limitations. Regarding the RII and the SII, the regression estimate of the relationship between health and the social dimension should not show significant deviations from linearity otherwise the magnitude of the index would be biased. This assumes a linear (positive or negative) relationship between health and the socioeconomic ranking, i.e. moving up in the social ranking gradually increases (or gradually decreases) the health outcome. However, this relationship is sometimes curvilinear 11 on actual data, and as a result, the RII and AII might be mis-estimated 12 . To Social inequalities in health-related behaviours:

Chapter 1 Is the grass greener on the other side?

-37 -overcome this issue, Sergeant and Firth (2006) proposed to model the relationship between health and the socioeconomic ranking using cubic splines rather than linear regression. However, this approach seems to be less relevant when socioeconomic ranking is not continuous and composed of few categories.

Although the CI does not require an assumption of linearity, it may fail detecting inequality. If the relationship between health and socioeconomic position is curvilinear, the concentration curve will cross the diagonal and the resulting CI will be close to zero, and thus, be unable to detect inequality.

In conclusion, the use of the CI, the RII and SII presents important advantages for cross-country comparison although some drawbacks need to be addressed carefully.

Bo ifa e " a d "helto N.

,

INTRODUCTION

Obesity and overweight rates have increased sharply in the last 20-30 years in OECD countries. The rise in obesity has reached epidemic proportions, with over one billion adults worldwide estimated to be overweight and at least three hundred million obese. [1] Many OECD countries have been concerned not only about the pace of the increase in obesity and overweight, but also about inequalities in their distribution across social groups. [2] Studies have shown a socio-economic gradient in obesity in a number of countries. Rates tend to be higher in disadvantaged socio-economic groups, whether disadvantage means poor education, low income or low occupation-based social class. [START_REF] Cutler | Education and Health: Evaluating Theories and Evidence[END_REF] found that people with more years of schooling in the US are less likely to smoke, drink a lot, be overweight or obese or use illegal drugs, and similarly, that the better educated are more likely to exercise and to obtain preventive care such as flu shots, vaccines, mammograms, pap smears and colonoscopies. [3] Jacobsen and Nilsen (2000) showed that people with higher education in Norway have less fat and more fibre in their diets. [4] Cross-sectional estimates from a study of twins also confirm the negative relationship between education and the probability of being overweight. [5] Although a socio-economic gradient exists in obesity, it does not appear to be as steep as that observed in general health status and in the prevalence of a number of chronic diseases. [6] This finding may be linked to substantial gender differences in the relationship between socio-economic status and obesity. In fact, the overall socio-economic gradient in obesity observed in many countries is an average of a strong gradient in women and a substantially milder gradient, or even the lack of one, in men. [7] Wardle et al. (2002) showed on English data, that obesity risk was greater in men and women with fewer years of education and in poorer economic circumstances, and among women, but not men, of lower occupational status. [8] A French study also found that, contrary to women, poorer men are less likely to be obese. [9] Most existing studies focus on individual countries and only few provide international comparisons.

Garcia Villar and Quintana-Domeque (2009) investigated the relationship between household income and body-mass index (BMI) in nine European countries showing an inverse relationship in women and mixed patterns for men, with higher BMI in men from higher-income groups in countries such as Finland and Portugal. [10] Mackenbach et al. (2008) -44 -to several health outcomes. [11] They focused on education-related inequalities in obesity showing that they were largest in women and in southern European countries. A meta-analysis of fruit and vegetable consumption studies found that adults from disadvantaged socio-economic groups in Europe have less healthy nutrition patterns. [START_REF] Grittner | Social Inequalities and Gender Differences in the Experience of Alcohol-Related Problems[END_REF] This paper contributes to the existing evidence through an international comparison of social inequalities in obesity and overweight across 11 OECD countries, including several European countries, Australia, Canada, Korea and the United States. Relative to previous comparative studies, this paper broadens the analysis of inequalities to measures of overweight, in addition to obesity, and looks at inequalities by both socio-economic status and education level. Moreover, this paper provides an original analysis of trends in inequalities over time, examining the prevalence of obesity and overweight in different social groups over the past 15 years.

METHODS

Data

Health survey data were obtained from 11 OECD countries: Australia, Austria, Canada, England, France, Hungary, Italy, Korea, Spain, Sweden and the United States. These countries provide a relatively wide geographical spread as well as a varied selection in terms of population rates of obesity and overweight (see Supplementary file No.1). All cross-sectional survey waves available for the last 15 years were used in the analysis.

Survey-specific sampling weights were used when appropriate (Australia, Canada, Hungary, Sweden and the US) and additional special weights were calculated to account for differences in sample size between survey waves. Analyses focused on respondents aged 16 to 65 who reported all the required individual characteristics (gender, age, ethnicity, marital status, education level, socio-economic status, occupation status, smoking status, height and weight). BMI was calculated as weight in kilograms divided by square height in meters. Obesity and overweight were then determined as a BMI equal to or greater than, respectively, 30 and 25.

Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side? -45 -Education levels were standardised across countries using the ISCED international classification of educational attainment. [START_REF] Stockwell | Under-reporting of alcohol consumption in household surveys: A comparison of quantity-frequency, graduated-frequency, and recent recall[END_REF] The relevant variable was categorized into three groups: up to primary school education; lower secondary school education; and, upper secondary school education or more. Socio-economic status was determined either on the basis of household income or occupation-based social class. Household income was equivalised to account for differences in household size and composition. Occupation was standardised across countries using the ISCO international classification and grouping occupations into five levels, following the model of the English socio-economic classification. [START_REF] Boniface | How is alcohol consumption affected if we account for underreporting? A hypothetical scenario[END_REF][START_REF] Meier | Adjusting for unrecorded consumption in survey and per capita sales data: Quantification of impact on gender-and age-specific alcohol-attributable fractions for oral and pharyngeal cancers in Great Britain[END_REF] Occupation-based social class could be derived for Austria, England, France, Hungary, Italy, Spain and Sweden. An occupation-based social class variable could not be derived for Australia, Canada, and Korea, and equivalised household income (in quintiles) was instead used as an indicator of socio-economic status. Finally, a ratio of family income to poverty was used to categorize socio-economic status for the US.

Health examination surveys involving a direct measurement of height and weight were available for England, Korea and the US, whereas other surveys are based on personally administered questionnaires and collect self-reported data on height and weight.

Inequality measures

Absolute and relative indexes were calculated to assess social inequalities in obesity and overweight.

These indexes are based on logistic regression estimates of obesity and overweight rates for every socioeconomic group. Logistic models were adjusted for a range of relevant covariates: gender, age (assuming a non-linear relationship with obesity and overweight), year of the survey, marital status, ethnicity (when available, i.e. in England and the US), smoking status, occupation status, education attainment, socioeconomic status and interaction terms between the latter and gender and between education and gender. The use of regression-based inequality indexes makes cross-country comparisons possible when the relative size of social groups varies in different countries.

The absolute, or slope, index of inequality is defined as the slope of the regression line marking the relationship between obesity (or overweight) and the relevant socio-economic variable. The absolute index is obtained using weighted least squares regression as data are grouped. [START_REF] Rehm | Statistical modeling of volume of alcohol exposure for epidemiological studies of population health: the US example[END_REF] The slope index provides a measure of the absolute size of inequalities, i.e. the difference between the rates estimated for those at the lowest and those at the highest ends of the social scale.

Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side?

-46 -The relative index of inequality is the ratio of the rates estimated for those at the lowest and the highest ends of the social scale. Therefore, the relative index is not sensitive to the overall prevalence of obesity or overweight within a given country. [START_REF] Ely | Methods of estimating individual levels of alcohol consumption in the general population[END_REF][START_REF] Midanik | The Validity of Self-Reported Alcohol Consumption and Alcohol Problems: A Literature Review[END_REF] All analyses were conducted using Stata 10.

RESULTS

Inequalities by education level

Values of the absolute index of inequality in the 11 OECD countries are displayed in Figure 1. Differences of up to nearly 12 percentage points in obesity rates are observed in men and up to 19 in women, with Spain and Hungary displaying the largest absolute inequalities. Larger education-related inequalities are consistently observed in women than in men, except in Austria. Absolute inequalities tend to be larger in countries with a higher overall prevalence of obesity and overweight, although a large gap is observed in France, where prevalence is relatively low, especially for obesity in men. The absolute index is negative for Korea, but its value is close to 0.

Absolute inequalities in overweight (Figure 1, Panel B) are larger than those in obesity for both genders.

France displays the largest inequalities with a 20 percentage point difference in overweight rates between the least and the most educated men. Indexes for Korea and the US are both negative, although the education gradient for the US is not linear, with the highest rates observed in men with intermediate levels of education. The absolute index for overweight in women varies between 12.5 and 44.4, with the largest values for Spain, Korea and Hungary. Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side?

-47 -Relative inequalities vary substantially across countries (Figure 2). France, Sweden, Austria, Spain and Italy present the largest inequalities in obesity. The least educated women in Spain, Korea, Italy and France, are over four times as likely as the most educated ones to be obese. Relative inequalities in overweight (Figure 2, Panel B) are substantially smaller than those observed in obesity, but the ranking of countries is similar, with the largest inequalities observed in France, Sweden and Austria for men and in Korea, Spain and Italy for women. Relative index 18 17 Men Women Men of the lowest socio-economic status are less than twice as likely to be obese as those at the opposite end of the social spectrum in all countries except France, where the relative index of inequality has a value of 2.4 (Figure 4). For women, the variation across countries in relative inequalities is wider, with

France and Sweden topping the ranking. Relative inequalities in overweight follow a similar pattern to absolute inequalities, with relatively small gradients in different directions (pro-rich in some countries, pro-poor in others) in men, and larger inequalities in women, consistently in favour of those with a better socio-economic status. The degree of inequality appears to be inversely related to the overall prevalence of obesity and overweight. Countries with higher prevalence rates tend to have smaller inequalities (see age- Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side?

-49 -standardised prevalence rates in Supplementary File No.1). Men in France and Sweden have a low prevalence of obesity and the largest relative inequalities by education level. Similarly, men in France and Austria have the largest inequalities by socio-economic status. Similar patterns are observed for women.

Trends in inequalities across education levels

The availability of multiple health survey waves for most of the countries examined provided an opportunity to explore trends over time in social inequalities. Obesity and overweight rates for different social groups in eight countries (Australia, Canada, England, France, Italy, Korea, Spain and the US) since the early 1990s are displayed in a series of graphs in Supplementary File No.2. Rates are adjusted for demographic and socio-economic covariates. Trend lines for different groups are broadly parallel in most countries, suggesting that obesity and overweight rates have grown uniformly across the socio-economic spectrum. However, a small narrowing of inequalities by education level was observed in England, France, and Korea (interaction Wald-test significant at the 95% confidence level), and a small increase was observed for overweight in Italian men.

DISCUSSION

This paper provides evidence of significant social inequalities in obesity and overweight in 11 OECD countries. Disparities in obesity tend to be noticeably larger than disparities in overweight, both for men and for women. This is in line with the fact that the highest levels of BMI are often observed among the poorly educated and more generally among those in disadvantaged socio-economic circumstances. The size of inequalities varies across countries and between genders. Women in disadvantaged socioeconomic groups are consistently more likely to be obese or overweight than more educated and affluent women. In men, smaller or no inequalities by education level were detected, while reverse (pro-poor) inequalities by income or occupation-based social class were found in several countries. The growth in obesity and overweight rates in the last 15 years in the countries examined has been broadly uniform across social groups, and inequalities have remained remarkably stable.

The findings reported here are consistent with previous reports that education-related inequalities in obesity are larger in women and in southern European countries. [11] Gender differences in degrees of inequality observed in this and other studies may be partly explained by a reverse causal effect linking obesity with poor labour market outcomes in women more often than in men. In particular, Garcia Villar and Quintana-Domeque emphasise the potential role played by larger wage penalties suffered by women in the labour market. [10] Other possible explanations include the stronger two-way link between obesity and unemployment in women. [START_REF] Hill-Mcmanus | Estimation of usual occasion-based individual drinking patterns using diary survey data[END_REF][20][START_REF] Ekholm | Influence of the recall period on self-reported alcohol intake[END_REF] A further channel through which inequalities develop is marriage and partner selection, as there is evidence that obesity reduces the probability of marriage in women. [START_REF] Ekholm | Influence of the recall period on self-reported alcohol intake[END_REF] Similarly, evidence from a longitudinal study has shown that overweight women are more likely to be unmarried, have lower education and lower incomes, while these effects are weaker in men. [22] Men and women in disadvantaged socio-economic groups may also differ with regard to their patterns of physical activity. Low-paid jobs typically reserved to men tend to be more physically demanding than those more often taken up by women. Finally, the link between malnutrition in childhood and obesity in adulthood may be an additional reason since Case and Menendez (2007) showed on South African data that women who were nutritionally deprived as children are significantly more likely to be obese as adults, while men who were deprived as children face no greater risk. [23] Gender differences in socio-economic gradients have important implications. Among other things, the higher prevalence of obesity in women belonging to disadvantaged socio-economic groups means that these women are more likely to give birth and raise children who will themselves be overweight or obese, and in turn will have fewer chances of moving up the social ladder, perpetuating the link between obesity and socio-economic disadvantage. A number of studies gave evidence on mother to child transmission of obesity. [24] Acting on the mechanisms that make individuals who are poorly educated and in disadvantaged socio-economic circumstances so vulnerable to obesity, and those at the other end of the socio-economic spectrum much more able to handle obesogenic environments, is of great importance not just as a way of redressing existing inequalities, but also because of its potential effect on overall social welfare.

Beyond the gender difference, it is observed that education-related inequality indexes are higher than socio-economic inequality indexes. Similarly, [START_REF] Costa-Font | What lies behind socio-economic inequalities in obesity in Spain? A decomposition approach[END_REF] found that formal educational captures a large share of the income-related inequality in obesity. The authors suggest as a possible explanation that the effects of unobservable factors like knowledge and social environment may possibly pass through education. [25] More educated people have a better knowledge on health risks, in particular, the risk of obesity, and so, they are less affected by obesity problem. [26] The effects of education on obesity are strengthened by social interactions with similarly educated peers, as there is evidence that health-related behaviours often spread through social networks. [27] In addition, another Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side?

-51 -possible explanation is that the education effect on obesity may reflect unobservable factors like time preference. [25] There is plausible evidence that time preferences based on a higher discount rate lead to less exercise and greater caloric intake. [28] It is more difficult to find an explanation for the different degrees of inequality observed across countries.

It appears clearly that countries with a higher overall prevalence of obesity and overweight tend to have milder inequalities (but not without exceptionssuch as Spain), suggesting that higher socio-economic groups may have caught up with others in terms of obesity and overweight, as overall rates increased.

However, our analysis of trends over time in inequalities clearly shows that obesity and overweight have grown in a similar way in all social groups. It is possible that inequalities may have narrowed in countries with a higher prevalence at an earlier stage of the obesity epidemic, when rates were growing faster than they are now. But longer time series are needed to test this hypothesis.

Extensive efforts were made to overcome data heterogeneities, over time and across countries, particularly in relation to education, income and occupation-based social class variables. One remaining issue is the heterogeneous nature of BMI measures used to assess obesity rates (measured in some countries, self-reported in others). Obese and overweight people tend to under-estimate self-reported weight. [29][30][31] To address this problem, algorithms have been proposed to adjust BMI values for selfreport bias, based on US data from the National Health and Nutrition Examination Surveys (NHANES). [START_REF] Van Kippersluis | al ool e F a e: uelles so t les populations à risque ? IRDES Questio d'Éco o ie de la Santé 129[END_REF][33] Unfortunately similar algorithms are not available for other countries, therefore this approach could not be used here. However, assuming a broadly consistent reporting bias across socio-economic groups, the absolute inequalities index may be under-estimated but the relative index should not be affected. A second remaining source of heterogeneity is that socio-economic status was determined on the basis of household income in four countries (Australia, Canada, Korea and the US) and occupation-based social class in the rest. Whether this may contribute to explaining the positive correlation between socioeconomic status and overweight observed in the former four countries for men, as well as in Canada and Korea for obesity, is impossible to determine on the basis of existing data, although recent studies on the relationship between income and BMI lend some support to these findings. [9][10] Social inequalities in health-related behaviours: 1995,1996,1997,1998,2000,2002,2004,2006 67,780 proportions, with over one billion adults worldwide estimated to be overweight and at least three hundred million of those considered to be clinically obese (WHO, 2003). The circumstances in which people have been leading their lives over the past 20-30 years, including physical, social and economic environments, have exerted powerful influences on their overall calorie intake, on the composition of their diets and on the frequency and intensity of physical activity at work, at home and during leisure time. On the other hand, changing individual attitudes, reflecting the long-term influences of improved education and socio-economic status (SES) have countered to some extent environmental influences.

Many OECD countries have been concerned not only about the pace of the increase in overweight and obesity, but also about inequalities in their distribution across social groups, particularly by level of education, socio-economic status and ethnic background. Inequalities across social groups appear to be particularly large in women (Wardle et al., 2002;[START_REF] Branca | Socioeconomic inequality in obesity in Europe: issues and policy implications[END_REF]. Acting on the mechanisms that make individuals who are poorly educated and in disadvantaged socio-economic circumstances so vulnerable to obesity, and those at the other end of the socio-economic spectrum much more able to handle obesogenic environments, is of great importance not just as a way of redressing existing inequalities, but also because of its potential effect on overall social welfare. The current distribution of obesity appears particularly undesirable, as it is likely to perpetuate the vicious circle linking obesity and disadvantage by intergenerational transmission.

Research has produced ample evidence of the individual labour market returns of education.

Economists Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side?

-66 -However, the causal nature of the link between education and health is still subject to a certain degree of scrutiny, and the precise mechanisms through which education may affect health are not yet fully understood. Lifestyles may be one of the keys to understanding such relationship, as they are often significantly influenced by education and, at the same time, they contribute to health and longevity by affecting the probability of developing a wide range of diseases. Obesity is a close marker of important aspects of individual lifestyles, such as diet and physical activity, and is also an important risk factor for major chronic diseases, such as diabetes, heart disease, stroke and certain cancers. Obesity is also associated with negative labour market outcomes, in term of both wages and employment, particularly for women (Cawley, 2004;[START_REF] Brunello | Does Body Weight affect Wages? Evidence from Europe[END_REF].

The aim of this paper is to provide new evidence concerning the relationship between education and obesity and contribute to understand the nature of such relationship and its implications for health and education policy. The empirical analyses on education and obesity undertaken by the OECD focus on four countries: Australia, Canada, England and Korea. Data from health surveys regularly undertaken in the four countries were used in a range of analyses, in pursuit of the following specific objectives: The a al ses e e o du ted appl i g the sa e odels to all ou t ies data, i o de to fa ilitate comparisons across countries. However, differences in data and survey methods sometimes make it difficult to achieve complete consistency. For instance, data on height and weight were measured by examination in England and Korea while they were self-reported in the other two countries. The education variable was obviously a critical one, and the format of this variable varied across countries.

We created a variable reflecting the numbers of years spent by each individual in full-time education using all the information available in each dataset on years of schooling and educational attainment. For consistency, we grouped together individuals with no education and those with the lowest level of education, as these two groups were not always separated in the available datasets. A certain degree of heterogeneity was also present in relation to the socio-economic status (SES) variable, as occupationbased social class was reported in the English data, while equivalised household income was available in Australia, Canada and Korea. Individuals were allocated to income quintiles in Australia and Korea, and to income groups based on fixed income ranges in Canada. Finally, an ethnicity variable was available in England, while proxies were used in Canada (minority status) and Australia (migrant status). No such variable was available in Korea. Tables of descriptive statistics are presented in Annex 1.

Existing evidence on the relationship between education and obesity

The existing evidence concerning the relationship between education and obesity is relatively limited, as the main focus of most research has been more broadly on the links between socio-economic factors and health status, or longevity, with a smaller number of studies focusing on lifestyles and on obesity in particular. The evidence available, covering a number of OECD countries, generally shows strong associations between education and obesity. However, there have been only few studies that have investigated the causal effects of education on obesity, and these studies have reported mixed results.

Cutler and Lleras-Muney ( 2006) found that those with more years of schooling are less likely to smoke, drink a lot, to be overweight or obese or to use illegal drugs. Similarly, the better educated are more likely to exercise and to obtain preventive care such as flu shots, vaccines, mammograms, pap smears and colonoscopies. They also found the relationship between education and health appears to be non-linear for obesity, with increasing effects of additional years of schooling. A review by Grossman and Kaestner concluded that years of formal schooling is the most important correlate of good health [START_REF] Grossman | Effects of Education on Health[END_REF]. Cross-sectional estimates from a study of twins conducted by Webbink et al. (2008), also confirms the negative relationship between education and the probability of being overweight. By looking at differences between the sexes within a study of socio-economic factors and obesity, [START_REF] Yoon | Socio-Economic Status in Relation to Obesity and Abdominal Obesity in Korean Adults: A Focus on Sex Differences[END_REF] found that income, rather than education, had a greater effect on BMI and waist circumference in men, whereas higher levels of education for women resulted in lower BMI and waist circumference.

The correlation between education and health may reflect three possible types of relationships: (a) a causal link running from increased education to improved health, (b) a reverse causal link, indicating that better health leads to greater education; or (c) an absence of a causal relationship between education and health, which appear to be correlated because of possible unobserved factors affecting both health (or obesity) and education in the same direction. The three pathways are not mutually exclusive, of course, and some combination of the three is likely to provide the most plausible explanation of the strong correlations consistently found across countries between education and health, or obesity. [START_REF] Cutler | Education and Health: Evaluating Theories and Evidence[END_REF] argue that children in poor health obtain less schooling and because of this they are also more likely to be unhealthy adults. Similarly, evidence on longitudinal data shows that becoming overweight during the first 4 years in school is a significant risk factor for adverse school outcomes in girls [START_REF] Datar | Childhood overweight and elementary school outcomes[END_REF]. Unobserved factors possibly contributing to the third Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side?

-69 -pathway identified may include family background, genetic traits or other individual differences, such as ability to delay gratification. These factors may explain why the more educated are also healthier. [START_REF] Cutler | Education and Health: Evaluating Theories and Evidence[END_REF] found that even controlling for some of these factors, the effect of education on health generally remains large and significant. Although there is evidence to support the hypothesis that the direction of causality is from more schooling to better health [START_REF] Grossman | The Human Capital Model[END_REF], when overall health status or longevity are the outcomes of interest, there are few studies shedding light on the causal nature of the relationship between education and obesity specifically. Results from Lundborg (2008) suggest that a causal effect of education on health exists, but found no evidence that lifestyle factors such as smoking and obesity contribute to the health/education gradient. Natural experiments where policy changes are implemented that directly affect the number of years of mandatory schooling, can provide an indication of the causal nature of the link between education and obesity. Arendt (2005) used changes in compulsory education laws in Denmark and found inconclusive results regarding the effect of education on BMI. However, Spasojevic, (2003) using a similar estimation strategy for Sweden found that additional years of education have a causal effect on maintaining a healthy body mass index. [START_REF] Clark | The Effect of Education on Adult Mortality and Health: Evidence from the United Kingdom[END_REF] focused on an educational reform implemented in England in 1947, which increased the minimum compulsory schooling age in the country, from 14 to 15. They found that cohorts affected by the law display only slightly improved long-run health outcomes and their findings did not support a causal link between education and obesity. [START_REF] Brunello | Years of Schooling, Human Capital and the Body Mass Index of European Females[END_REF] used compulsory school reforms implemented in European countries after the II World War to investigate the causal effect of education on the BMI and the incidence of overweight and obesity among European females. They showed that years of schooling have a protective effect on BMI. On US data, Grabner (2009) used the variation caused by state-specific compulsory schooling laws between 1914 and 1978 as an instrument for education, and found a strong and statistically significant negative effect of additional schooling on BMI, effect especially pronounced on females.

Mi hael G oss a s de a d fo health odel, de eloped i the s, h pothesised that s hooli g aises a pe so s k o ledge a out the p odu tio elatio ship a d the efo e i eases his o her ability to select a healthy diet, avoid unhealthy habits a d ake effi ie t use of edi al a e [START_REF] Kemna | Working Conditions and the Relationship between Schooling and Health[END_REF]. Educated individuals make better use of health related information than those who are less educated. Education provides individuals with better access to information and improved critical thinking skills. [START_REF] Speakman | Associations between BMI, Social Strata and the Estimated Energy Content of Foods[END_REF] hypothesised that the lack of education about energy contents of foods may contribute to the effects of social class on obesity. Results from their study show that on average, non-obese individuals in the lower social class group have better food knowledge than those Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side?

-70 -who are obese in the same group. However non-obese subjects in all groups overestimate food energy in alcoholic beverages and snack foods indicating poorer knowledge of the energy content of these foods.

Lack of info atio ould also affe t o e s o pe eptio a out thei od ass. 'esea h has sho that over time more overweight individuals are under-perceiving their body mass compared to people with normal weight [START_REF] Haas | Weigh Too Fat[END_REF]. It is possible that more highly educated people have the knowledge to develop healthy lifestyles and have more awareness of the health risks associated with being obese [START_REF] Yoon | Socio-Economic Status in Relation to Obesity and Abdominal Obesity in Korean Adults: A Focus on Sex Differences[END_REF]. The more educated are more likely to choose healthy lifestyles; however, it has been shown that the highly educated choose healthier behaviours than individuals who are highly knowledgeable about the consequences of those behaviours [START_REF] Kenkel | Health Behavior, Health Knowledge, and Schooling[END_REF]. This could indicate that the effect of education on obesity is driven by different mechanisms, and not just by information and knowledge about healthy lifestyles.

Exploring the link between education and obesity is important, as this may lead to the development of appropriate education-based policies to counteract recent trends in obesity and related chronic diseases. For example, if the findings reported by [START_REF] Cutler | Education and Health: Evaluating Theories and Evidence[END_REF] showing increased effects of additional years of schooling for those who are better educated were confirmed by further analyses, these would provide support for education policies aimed at promoting higher education, as these would produce greater health returns.

Policy and institutional environment

Policies aimed at counteracting the negative effects of obesity through the education system can be of two main types: policies focusing on the educational environment, aimed at promoting healthier lifestyles by exposing children to healthier environments and by providing health education; and policies aimed at encouraging higher levels of general education. Although the relationship between years of schooling, or educational attainment, and health outcomes is well established, most of the policies encountered to improve health by promoting lifestyle changes have focused on educating the population about healthier lifestyles as opposed to providing more general education. Each of the four countries e a i ed i this stud ha e i ple e ted poli ies to st e gthe health li i g edu atio ithi schools, with the aim of achieving better health outcomes.

General trends in obesity in the four countries

The distribution of BMI in the four countries concerned has been shifting in a characteristic fashion over the past few decades, as illustrated in [START_REF] Sassi | Improving Lifestyles, Tackling Obesity: The Health and Economic Impact of Prevention Strategies[END_REF] In particular, as in most OECD countries, a sizable share of the normal weight population has been progressively gaining weight, moving towards the pre-obese category first, then progressively towards obesity and, in some cases, morbid obesity (BMI>40). A visible increase in the percentage of the population that is obese was recorded for both men and women, across all four countries (Figure 1). However, a significant difference in trends between genders is observed in Korea, where the relative distribution of females over the BMI categories remained relatively stable between 1998 and 2005, while a 10% decrease in the normal weight category was observed in men, followed by a 9% increase in the pre-obese category and a 2% increase in the obese category. On the other hand, in 2005 Korea had only 4% of its population obese, on average, compared to 25% in England, 18% in Australia and 17% in Canada. In the latter three countries the percentage of overweight men is significantly higher than that of women. In Canada, the majority of men were overweight in all survey years, and the same has been true in England since 1995. Age-standardised obesity rate for men aged Age-standardised obesity rate for women aged 15-64

"ou e: Autho s esti ates usi g OECD sta da d population.

BOX 2: Methods

Differences in obesity rates among population groups with different levels of education were first analysed using logistic regression models controlling for a range of covariates, including gender, age, ethnicity, SES and survey year (Figure 2 and Annex 2). An interaction term between education and gender was also included in the regression model for the purpose of assessing differences between the two genders in the relationship between education and obesity (Figures 4 to 6, and Annex 3). The relationship between education and obesity in different ethnic groups was similarly explored through an interaction term between years of education and ethnicity (minority status in Canada, migrant status in Australia).

The relationship between BMI and education was analysed using ordinary least squares regression models including the same covariates listed above (Figure 3 and Annex 2). All analyses were conducted using Stata 10.

Obesity rates, as well as BMI levels, by years of education were reported in separate graphs for different population groups. The linearity of the relationship between education and obesity and BMI was assessed visually, based on those graphs.

The effects of the clustering of individuals into households or geographical areas were studied using multilevel statistical models, also known as hierarchical linear models, random effects models or nested models (see Annex 4). Multilevel analyses concerned England and Korea data which are based on household structure. Two-level random-intercept models, using households as higher-level units of -74 -aggregation, were tested on samples of people aged 25-64, living in household comprising at least two members. It was not possible to perform this analysis on Australian and Canadian data, since the relevant surveys do not have a household structure.

Is the strength of the correlation between education and obesity constant across the entire education spectrum, overall and in different population subgroups?

Figure 2 shows the relationship between education and obesity for each gender in the four countries. Obesity rates in Figure 2 and BMI levels in Figure 3 are regression estimates adjusted for age, gender, and socio-economic status. Full results are presented in Annex 2. The relationship is negatively sloped in all cases except in Korean man, indicating that each additional year of education is consistently associated with a lower chance of being obese in Australia, Canada and England, as well as in Korean women. For Korean men, no conclusive results could be obtained as none of the coefficients for education were significant in the regression analysis, possibly due to the relatively small number of individuals who are obese in the country. The patterns shown in Figure 2 suggest that the relationship between obesity and years of education may be considered broadly linear, i.e. of a constant strength across the entire education -75 -spectrum. However, results for England and Canada might suggest that the effect of further years of education tends to decrease progressively when approaching completion of upper secondary education (13-14 years of schooling), and then increase again sharply in individuals who complete tertiary education. A similar effect was also found for men in Australia, based on 2001 and 2005 data, which provided more detailed information on years of education relative to other editions of the same survey.

When the relationship between average BMI and education is observed, as in Figure 3, the conclusions are similar to what was previously discussed. No clear and consistent deviation is observed from a linear pattern in the four countries examined. Again Korean men represent an exception, as they display a positively sloped relationship, which seems substantially more marked than in Figure 2, where the link between education and obesity was examined. Australia to denote, respectively, ethnic minority status and migrant status. The slope of the correlation between education and obesity is broadly similar in women, across all ethnic groups, although Black women display significantly higher obesity rates than others. It is difficult to assess whether the different patterns observed in Black and Asian women, suggesting a concave relationship between education and obesity in the former and a convex relationship in the latter, reflects a true difference in the impact of -76 -education in the two groups. However, this interpretation of concavity and convexity on few data points should be taken with caution, as it is sensitive to outliers. This finding demands a larger and more detailed investigation. Education appears to be much more weakly correlated with obesity in Black and Asian men, although the least educated among Black men are substantially more likely to be obese than their more educated counterparts. In Canada, individuals who belong to ethnic minority groups are less likely to be obese than White majority individuals. The relationship between obesity and education level is negatively sloped in both men and women, regardless of minority status, as illustrated in Figure 5. -77 -The analysis of the correlation between obesity and education in Australia does not show significant differences by migrant status, as illustrated in Figure 6. In addition, regression analyses presented in Annex 2 and 3 were adjusted for SES. Obesity tends to be more prevalent in disadvantaged socio-economic groups, and inequalities are consistently larger in women than in men. A more detailed analysis of social inequalities in obesity is presented in a separate study [START_REF] Devaux | Social inequalities in obesity and overweight in eleven OECD countries[END_REF].

Does the relationship between education and obesity reflect the role of other factors associated with individual education?

Several factors associated with individual education may potentially have an influence on the correlation observed between education and BMI/obesity. In particular, we studied the influence of individual socio-economic status and of the education level of household members.

In addition to its direct effect on the likelihood of obesity, individual education may also have an indirect effect, mediated by individual socio-economic status. -78 -effect of education on obesity 13 (c). In order to test for the existence of the hypothesised mediation effect, a series of logistic regression models were developed with and without controlling for the socioeconomic status covariate, to assess possible variations in the coefficients of the individual education variable. Results are consistent with a slight mediation role played by socio-economic status in the relationship between education and obesity since odds ratios of obesity according to education level change slightly towards a unitary value, when the role of socio-economic status is accounted for [START_REF] Sassi | The Obesity Epidemic: Analysis of Past and Projected Future Trends in Selected OECD Countries[END_REF]. However, it should be noted that this empirical strategy does not account for a potential reverse causality in the relationships outlined in Figure 7 (a, b andc). A further analysis focused on the education of household members, which might have a direct influence on the likelihood of an individual being obese, i.e. it may have a concurrent effect to that of individual education (relationships e and f in Figure 8). In principle, individual education may also act as a mediator of the household education effect on obesity (d and e in Figure 8). However, the analysis focused on the former (concurrent) effect of the education of household members.

Figure 8. Indirect effect of education of household members

The concurrent effect of household education could bias estimates of the effect of individual education on obesity. The education of household members could be, indeed, viewed as an omitted a ia le that ould ias the odel s oeffi ie ts. "o, to test fo this o u e t effe t, eg essio odels with and without this covariable were computed. This analysis is limited to England and Korea, the two countries for which household-based surveys are available. Multilevel logistic models were used to account for household structure (see Annex 4 for details of methods used). The education of household members is defined as the years of education of the spouse of the head of household and, when the latter was not available, as the years of education of the head of household. 14Odds ratios for the probability of being obese in England are displayed in Table 1. Model 1 is a multilevel logistic model without controls for the level of education of household member, whereas model 2 accounts for the education of household members. Differences among households explain about one fifth of the total variance in the likelihood of obesity (see the intra-class correlation coefficient Rho, in Table 1). It is worth noting that household education is negatively correlated to obesity status (odds ratio < 1) with significant values when years of education are above 11. Comparison of model 2 with model 1 shows that there seems to be a small concurrent effect of household education on obesity, which adds to the effect of individual education, since odds ratios of obesity according to individual education become smaller and closer to 1. Table 2 shows the results of the corresponding analysis for Korea. In this case, differences among households explain about 7% of the total variance in the likelihood of obesity (see intra-class correlation in Table 2). In both models, odds ratios for men are not significantly different from 1, although the -81 -strength of the correlation between obesity and individual education is somewhat diminished in model 2, similarly to what was observed in England. On the other hand, the correlation between individual education and obesity appears marginally strengthened when accounting for household education in women, contrary to expectations. However, the absence of a statistically significant correlation between household education and obesity prevents from drawing any conclusions on the role of the latter in Korea.

Do the data provide evidence of the causal nature of the link between education and obesity?

When exploring the cross-sectional relationship between obesity and education, it is difficult to interpret the direction of the causal link between the two variables. In addition, the correlations identified might be affected by the omission of relevant variables in the analysis.

The existence of a reverse causal effect (obesity in young age determines the level of educational achievement of an individual) is supported by the findings of several studies. [START_REF] Sargent | Obesity and Stature in Adolescence and Earnings in Young Adulthood[END_REF], using panel data, showed an inverse relationship between obesity at age 16 and earnings at 23 in young women. [START_REF] Gortmaker | Social and Economic Consequences of Overweight in Adolescence and Young Adulthood[END_REF] found that women who were overweight in childhood completed fewer years of school. [START_REF] Crosnoe | Body Mass Index, Academic Achievement, and School Context: Examining the Educational Experiences of Adolescents at Risk of Obesity[END_REF] found that students at risk of obesity achieved worse outcomes in schools characterized by higher romantic activity, lower mean BMI or lower rate of athletic participation, than they did in schools lower in romantic activity, higher in mean BMI or higher in athletic participation.

Since no suitable instrument for education was identified in the available survey data, nor could be linked from external sources, it was not possible to address endogeneity issues satisfactorily in the analysis. However, an attempt to explore the direction of the causal link between education and obesity was made possible by data from an additional country, France 15 . The data from Enquête Décennale Santé 2002-2003 provides information on body weight at age 20, which was taken to reflect obesity status at school age. The data shows that bei g o ese at age is positi el a d sig ifi a tl o elated ith obesity in adulthood (correlation 0.177) and is negatively and significantly correlated with the number of years spent in education (correlation -0.035). Figure 9 shows that those who were obese at age 20 have significantly lower levels of educational attainment than those who were not obese, suggesting a potential for reverse causality in the relationship between education and obesity. 15 A second test for the causal nature of the link between education and obesity was carried out using data from the Health Survey for England in a sort of natural experiment, assessing the impact of the educational reform introduced in England in 1973, which increased the minimum compulsory schooling age from 15 to 16 years. [START_REF] Clark | The Effect of Education on Adult Mortality and Health: Evidence from the United Kingdom[END_REF] used this approach with reference to an earlier educational reform implemented in England in 1947, which also increased the minimum compulsory schooling age in the country, from 14 to 15. They found that cohorts affected by the law display only slightly improved long-run health outcomes and their findings did not support a causal link between education and obesity. Our results consistently indicated an absence of change in the likelihood of obesity in the cohorts affected by the educational reform, relative to previous cohorts. This finding does not necessarily indicate that the link between education and obesity is not of a causal nature. Rather, it may suggest that school reforms leading to small changes in minimum compulsory schooling age do not provide sufficiently strong means for implementing an instrumental variables approach.

Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side? -83 - In order to assess the influence of such potential reverse causal effect on the observed correlation between education and adult obesity, the results of two regression analyses assessing factors associated with adult obesity were compared, in one of which the o esit at age a ia le as i luded as a additional covariate (Table 3). Comparing Model 1 (without control) and Model 2 (with control) is a way of assessing whether the strength of the association between education and obesity is affected by a potential reverse causality. Odds ratios of obesity relative to education for women are virtually identical in both models, while small changes are observed in odds ratios for men. This comparison suggests that a reverse causal effect is unlikely to have a significant influence on the strength of the correlation observed between education and adult obesity. However, there remains an issue of potential recall bias concerning body weight at age 20, as suggested by the fact that individuals tended to report round numbers (e.g. 60, or 65 kg).

What theoretical model of the influence of education on social outcomes is supported by the data?

As a final step in our empirical analysis, we assessed which of the absolute, relative and cumulative conceptual models of the outcomes of education proposed by Campbell (2006) is empirically supported by the data.

BOX 3: The absolute, relative and cumulative models

The relationship between education and obesity may be interpreted according to various models/hypotheses, which involve alternative mechanisms. Three such models were conceptualised by Campbell (2006) -85 -

The absolute model implies that the probability that individuals will be obese depends on their level of education. According to this model, education may reduce the probability that an individual will be obese both by increasing the stock of information available to the individual concerning the health risks associated with unhealthy lifestyles, and by improving their ability to understand and handle such information. When the effects of education are in line with the predictions of the absolute model, policies which successfully promote education and learning and increase the average educational attainment of a population will have the effect of decreasing obesity rates. While our hypothesis is that the absolute model of education generally leads to lower rates of obesity through increased education, the absolute effect of education might also be negative. If education increases wages, and therefore increases the oppo tu it ost of leisu e ti e, a edu ated i di idual s p ope sit to e gage i leisu e ti e ph si al activity or home meal preparation will likely be reduced.

The relative model i plies that edu atio se es as a a ke of so ial status a d a i di iduals le el of edu atio elati e to thei pee s , o elati e to the p e aili g le el of edu atio i the ele a t so ial environment, is what affects the probability that they will be obese. This model implies that a generalised increase in the level of education of an entire community may not alter individual outcomes, unless the relative position of individuals within that community changes as a result.

The cumulative model rests on the idea that the impact of individual education on obesity is consistent with, and additive to, the impact of the level of education of other members of the same community.

Therefore, the likelihood that an i di idual a e o e o ese depe ds oth o the i di idual s o level of education and on the level of education of other community members.

To test the above models, logistic regression analyses of the likelihood of obesity were run on the four countries data usi g a si ila app oa h to that p oposed Ca p ell i his a al sis of i i a d social engagement as an outcome of education. Regression models included, in addition to the control variables gender and age, two measures of education: the number of years of education completed by the individual respondent (education level) and the mean level of education completed by members of the same age cohort within the same country (educational environment). In order to calculate the educational environment variable, four 10-year birth cohort groups were devised : 1941-50, 1951-60, 1961-70, 1971-80. Mean education levels within each cohort were standardised using the 2005 national distributions of levels of education (lower secondary; upper secondary; tertiary education) by age group, available in Education at a Glance 2007 (OECD, 2007). Findings of a statistically significant and strong Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side? -86 -negative effect of individual level education on obesity would provide support for the absolute model. A positive correlation between educational environment and obesity could be interpreted as evidence of a relative effect of education, especially if the correlation is stronger than that between individual education and obesity. Findings indicating that individual education is negatively correlated with obesity and the educational environment variable is negatively correlated with obesity would lend support to the cumulative model, especially if the latter correlation were stronger than the former (Campbell, 2006). Table 4 indicates that better educated individuals are less likely to be obese than their less educated counterparts in all of the countries considered. This result can be viewed as evidence in support of the absolute effect of education model, mirroring evidence in the literature on the importance of individual level education for health status and health behaviours. However, after accounting for individual level education, those who are exposed to better educated environments in Australia, Canada and England are significantly more likely to be obese. This finding supports the relative model of the effects of education, which appears to play a larger role than the absolute model in explaining the distribution of obesity across social groups. Educational environment estimate is not significant in Korea which gives evidence for the absolute model. Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side? -87 -The relative effect could operate through several pathways. One pathway that is consistent with both the absolute and the relative models is that linking social position to stress levels and eventually to health outcomes. Evidence has been gathered that individuals who have a lower social position are exposed to higher levels of perceived stress, because of a lower degree of control over their jobs and their life circumstances and because of a less satisfactory balance between efforts and rewards (Siegrist and Marmot, 2004). This is associated with a reduced ability to handle environmental pressures and often translates into less healthy lifestyles, obesity, chronic diseases and premature mortality (Brunner et al, 2007;Chandola et al., 2008). A second pathway which typically reflects features of the relative model of the effects of education is linked to a higher demand for health inputs that are associated with a healthy weight, e.g. gym and health club memberships, by those who have higher levels of education and occupy higher social positions. In communities where the average level of education is higher, demand for such inputs, and consequently the price of those inputs, are also likely to be higher, hindering access to the same resources for the less educated and less well-off.

A further analysis was carried out to test for a possible effect of individual education on obesity, consistent with the absolute model discussed above. The analysis exploited age-period-cohort models of obesity developed by [START_REF] Sassi | Improving Lifestyles, Tackling Obesity: The Health and Economic Impact of Prevention Strategies[END_REF] with the aim of disentangling the effects of the three time-related factors (individual age, period of observation and birth cohort) on the likelihood of obesity. The findings of the main analysis showed negatively sloped cohort effects, suggesting that individuals born in more recent cohorts, other things being equal (including age), have a lower probability of being obese than individuals born in earlier cohorts, with a possible flattening of the cohort effect curve for the most recent cohorts. Here, these models were completed by adding a control for individual education, for the purpose of testing whether improvements in education over time may account for at least part of the negatively sloped cohort effects observed in the main analysis, i.e. whether a higher level of education may partly explain why individuals born in more recent cohorts have a lower probability of being obese.

The age-period-cohort model used in the analyses is the one proposed by [START_REF] Yang | A Methodological Comparison of Age-Period Cohort Models: the Intrinsic Estimator and Conventional Generalized Linear Models[END_REF], based on a robust estimator (intrinsic estimator) which does not require the identification of constraints on the parameter vector by using prior information. The intrinsic estimator method [START_REF] Fu | Ridge Estimator in Singular Design with Application to Age-Period-Cohort Analysis of Disease Rates[END_REF][START_REF] Knight | Asymptotics for Lasso-type Estimators[END_REF]Fu and Hall, 2004;Fu and Rohan, 2004) considers an orthogonal decomposition of the parameter space into a null space for the singular design matrix and a non-null space, where the intrinsic estimator is obtained by the Moore-Penrose generalized inverse. Analyses were carried out on data from Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side? -88 -Canada and England. Obesity rates in Korea are too low for this analysis to produce meaningful results, and Australian data were not directly accessible at the individual level.

An age-period-cohort analysis allowed to disentangle the impact of the three time-related effects on obesity. The findings of such analysis (reported in [START_REF] Sassi | Improving Lifestyles, Tackling Obesity: The Health and Economic Impact of Prevention Strategies[END_REF] show declining cohort effects in Canada, England and, to a lesser degree, in Korea (no APC analysis could be undertaken on Australian data). After inclusion of individual education as a covariate in the regression models for the two countries with more pronounced cohort effects, trends in cohort effects become more flat (Figures 10 and11). This means that part of the reduction in the likelihood of obesity in younger birth cohorts is explained by their higher degrees of educational attainment achieved by individuals in the same cohorts, which is consistent with the absolute model of the effects of education on obesity.

Conclusions

A range of analyses of health survey data from Australia, Canada, England and Korea were undertaken with the aim of exploring the relationship between education and obesity. The findings of these analyses show a broadly linear relationship between the number of years spent in full-time education and the probability of obesity, with most educated individuals displaying lower rates of the condition (the only exception being men in Korea). This suggests that the strength of the correlation between education and obesity is approximately constant throughout the education spectrum. Increasing education at any point along that spectrum would be expected to reduce obesity to a similar degree, if the causal nature of the link between education and obesity had been established.

The education gradient in obesity is stronger in women than in men. Differences between genders are minor in Australia and Canada, more pronounced in England and major in Korea. The gradient has not meaningfully changed over the time periods covered by the health survey data available for our study.

However, there is at least some evidence that over longer periods of time more educated individuals Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side? -90 -have been less likely to be become obese than their less educated counterparts, suggesting that education produces its influence on obesity only in the long term.

The causal nature of the link between education and obesity has not yet been proven with certainty. Our own attempt to use a natural experiment, involving a school reform which increased the minimum compulsory schooling age in England by one year in 1973, failed to establish a causal link.

However, using data from France we were able to ascertain that the direction of causality appears to run mostly from education to obesity, as the strength of the association is only minimally affected when accounting for reduced educational opportunities for those who are obese in young age. Most of the effect of education on obesity is direct. Small components of the overall effect of education on obesity are mediated by an improved socio-economic status linked to higher levels of education, and by a higher le el of edu atio of othe fa il e e s, asso iated ith a i di idual s o le el of edu atio .

The positive effect of education on obesity is likely to be determined by at least three factors: (a) greater access to health-related information and improved ability to handle such information; (b) clearer perception of the risks associated with lifestyle choices; and, (c) improved self-control and consistency of preferences over time. However, it is not just the absolute level of education achieved by an individual that atte s, ut also ho su h le el of edu atio o pa es ith that of the i di idual s pee s. The highe the i di idual s edu atio elati e to his o he pee s , the lo e is the p o a ilit of the i di idual being obese. The latter effect may be due to different levels of perceived stress experienced by individuals in different social positions, and by different coping mechanisms. Access to resources required to ai tai a health eight a also e d i e a i di idual s positio i the so ial hie a h .

The findings reported in this paper concerning the relationship between education and obesity are consistent with those reported in a number of other studies, notably [START_REF] Spasojevic | Effects of Education on Adult Health in Sweden: Results from a Natural Experiment[END_REF], Arendt (2005), [START_REF] Kenkel | The Roles of High School Completion and GED Receipt in Smoking and Obesity[END_REF], Cutler andLleras-Muney (2006), Sánchez-Vaznaugh et al. (2009). Several of the above studies showed a strong education gradient in BMI or obesity, with the better educated, especially if women, less likely to be overweight or obese. We found similar evidence in all of the four countries examined, with the largest differences between genders in Korea, the only country in which an inverse gradient (more education associated with higher obesity rates) was observed in men. This used to be a common pattern in many countries early in the 20 th century, and it is possible that some countries which still display relatively low obesity rates, like Korea, still retain that feature as a sign of the slower transition they have been experiencing in the weight distribution across population groups. Cutler and Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side?

-91 -Lleras-Muney ( 2006) also found that the gradient in obesity was steeper in whites than in ethnic minorities. In our study, a detailed analysis by ethnic group could be undertaken using data from England, which showed substantially milder education gradients in obesity for minority men, relative to white men, but similar gradients in women of different ethnic backgrounds.

It should be noted that BMI was measured in England and Korea, but self-reported in Canada and Australia. The use of self-reported data may potentially cause bias in the results, as a number of people tend to report incorrectly their height and weight. However, there is no clear evidence that self-report bias may vary among individuals with different levels of education. Therefore, the correlations reported in this paper may not be affected in a major way by this potential limitation. Also, BMI is not an accurate measure of body fat, or body composition. For instance, those with a substantial muscular mass because of intense physical activity may have a high BMI but a low risk for chronic diseases. However, BMI is a widely reported measure which has proven to be particularly useful in population-level analyses. There is evidence that the link between BMI and the associated health risks is different in Asian populations, suggesting that lower BMI thresholds should be used in the latter to identify individuals who are overweight or obese. In the present study we applied the same thresholds in all countries.

The analyses presented in this paper were based on cross-sectional health survey data, which provide a very detailed source of information on the health and health-related behaviours of the respective populations, but at the same time present a number of limitations, especially in the assessment of the causal nature of the link between education and obesity. Individual education was defined as the number of years spent in full-time education, although this was available in a discrete form and interpolations were required. No information was available on the quality and contents of the education received, which are also likely to influence health and health-related behaviours in adult life.

Policy Implications

Establishing the causal nature of links between obesity and policy levers that could potentially be used to curb the current epidemic is essential for effective policies to be designed and implemented. If changes in education could be expected to influence health-related behaviours and obesity rates in a population, this might strengthen the case for educational policies aimed, for instance, at increasing compulsory schooling age or increasing enrolment in higher education. Our analysis in Table 4 provides Social inequalities in health-related behaviours:

Chapter 2 Is the grass greener on the other side? -92 -an estimate of the size of such effect. Increasing education by one year in the whole population would decrease the overall obesity rate by 4% in Canada, and up to 9% in England. [START_REF] Cutler | Education and Health: Evaluating Theories and Evidence[END_REF], with reference to the broader health effects of education, argued that if a causal link were proven, education subsidies might be desirable. These would promote higher levels of education for a larger share of the population and correspondingly improve population health. [START_REF] Grossman | Effects of Education on Health[END_REF] argued that education policies directed at disadvantaged groups might reduce some of the existing health disparities. Although the evidence currently available, including some of the findings of our study, provides strong suggestions that at least part of the correlation between education and obesity is of a causal nature, a conclusive proof of this does not yet exist.

Health education programs aimed at promoting healthy lifestyles might in principle generate similar effects to those associated with school education by providing relevant information. However, Speakman et al. a gue that these a paig s a e likel to e i effe ti e if people i lo e so ial strata already know what foods have high energy contents, ut fail to a t o this i fo atio , suggesti g that health promotion would mostly help those who have a higher level of education. However, very limited empirical evidence exists concerning the effects of health education programmes, and virtually none is available on differences in effectiveness between socioeconomic groups. [START_REF] Haas | Weigh Too Fat[END_REF] suggested that more funding should not be spent on public health education campaigns while clear evidence of the effectiveness of such programs does not exist.

Whether through formal schooling or health promotion campaigns, education may play a role in tackling overweight and obesity. Policy makers need to consider what levels of evidence should be deemed sufficient to prompt action, and how efficiency and equity objectives should be balanced in tackling obesity. Education policies aimed at increasing formal schooling include a flexible range of policies, which may be targeted at specific age and socioeconomic groups. We showed that the strength of the link between education and obesity is approximately constant throughout the education spectrum, which means that similar gains could be achieved in terms of reduction of obesity rates by increasing educational attainment for early school leavers as well as for those who spend the longest in full time education. However, policies targeting early school leavers would likely improve equity by focusing on individuals who are more likely to belong to disadvantaged socioeconomic groups. Similar results could be achieved by improving access to education, e.g. through financial incentives, for disadvantaged groups.

ANNEXES Annex 1. Data description tables

Annex 2. Regression analysis related to estimates in Figures 2 and 3

Logistic regression was used to estimate the likelihood of obesity associated with different lengths of time in education for both genders.

Annex 4. Multilevel models

This methodological annex gives a description of the multilevel model. Let y i be the value of the response variable Y for the individual i, and X 1 an independent covariate in a simple univariate model, the single-level regression equation for the individual i is given by

i i i e x y    1 1 0   (1)
where β 0 is the intercept, β 1 the regression coefficient and the individual-level residuals e i with e i ~ N(0, σ e 2

).

In order to evaluate the significance of a higher order aggregation of individuals in n groups on the single values y i , the regression model in ( 1) can be written as (2) where j = 1,…, n refers to the level-2 units (groups) and i = 1,…, N, to the level-1 units (individuals).

Model in equation ( 2) is called random intercept model when the intercept β 0 in (1) becomes a random variable depending on the group j, that is

j j u 0 0 0     (3) with u 0j ~ N(0, σ u0 2
) as group-level residuals. When considering also the regression coefficient β 1 as a random variable such as

j j u 1 1 1     (4) with u 1j ~ N(0, σ u1 2
) and cov(u 0j ,u 1j ) = σ u01 , the model in equation ( 2) is called random coefficient model and can be written in the form

) ( 1 1 0 1 1 0 ij ij j j ij ij e x u u x y        (5)
In equation ( 5) the response variable y ij has been expressed as the sum of a fixed part and a random part within the brackets, where the covariate x 1ij in the random part of the model is usually substituted by z 1ij to make the distinction with the covariates in the fixed part. In model ( 5) both intercept and regression oeffi ie ts a f o g oup to g oup, so to e plai the effe t of the g oup s agg egatio o the Y variable. The individual-level residuals e ij are assumed to be independent from the group-level residuals u 0j and u 1j .

The intra level-2 unit correlation in random intercept models is given by

2 2 0 2 0 e u u       (6) ij ij j j ij e x y    1 1 0  

INTRODUCTION

Harmful alcohol use is responsible each year for about 2.5 million premature deaths worldwide. 1 To design appropriate public health policies, it is important to understand how far hazardous drinking (HD) spreads and which population groups are the most affected. A number of studies examined differences in HD by gender and socioeconomic background; however findings are not always consistent, largely due to the variety of HD outcomes used. There is evidence of a negative association between education and heavy drinking. 2-4 However, evidence on the relationship between socioeconomic status (SES) and HD is less consistent. A US study shows that heavy episodic drinking is more prevalent among people with higher incomes. However heavy episodic drinkers with lower incomes do so more frequently and consume larger numbers of drinks. 5 Men are more often drinkers and consume more alcohol than women. 2 Gender differences in drinking are intertwined with educational and socioeconomic gradients in harmful drinking. A British study shows a strong positive link between educational attainment and drinking frequency as well as life-time drinking problems in women, but no such association in men. 6 International studies show that men with lower education are more likely to be hazardous and heavy episodic drinkers, 2,7-8 whereas more educated women are more at risk but with some exceptions, e.g. Czech Republic, Finland, Hungary, and Sweden. 2,7,9 It is worth noting that despite the multi-country framework, there was no attempt to gauge and compare the size of social disparities across countries in the above studies.

Besides, there is evidence that people in lower SES groups and ethnic minority groups are more affected by alcohol-related harms. In a number of countries, the worst-off have higher rates of alcohol-related problems and mortality than the better-off, 10 even for the same level of drinking. 11-12 These disparitiesobserved for equal alcohol consumption-are possibly the results of other social or environmental dimensions surrounding problems such as health education or access to health care. These findings along with the picture of the social gradient in HD as described above may question about the reliability of drinking measurement in surveys and raise the issue of self-report bias.

Survey-based data on alcohol consumption are likely affected by measurement bias including underreporting by survey respondents, 13-17 and selection bias in survey sampling that may under-sample groups of people with high alcohol consumption (e.g. students, alcohol dependent people), and may not Social inequalities in health-related behaviours: Chapter 3 Is the grass greener on the other side? -114 -include at all people the most at risk of harmful drinking (e.g., homeless). 13,15 Drinking levels reported in household-based surveys have been shown to account for only 40-60% of alcohol sales. 18-19 Alternative data sources on alcohol consumption exist, but they generally do not permit to analyse drinking behaviours by SES. WHO produces aggregate estimates of adult per capita alcohol consumption (APC) including recorded consumption -based on sales, tax, international trade, and survey data-and unrecorded consumption adjusting for homemade or illegally produced alcohol, smuggled alcohol, alcohol for industrial and medical use, and tourist consumption. 1 The latter accounts for nearly 30% of total worldwide adult consumption. These aggregate APC estimates provide the most reliable information to determine broad national trends and draw country profiles of alcohol consumption. However, their aggregate nature does not permit identification and examination of individual drinking behaviours.

The drivers of mis-reporting alcohol consumption associated to survey design have been largely explored, 19,20-21 whereas predictors at the individual level such as level of drinking and socio-demographic factors need more attention. On one hand, a number of studies suggest that self-report bias and nonresponse bias may be larger among heavy drinkers. 22-25 On the other hand, differences in self-reporting consumption are suspected in relation to social and educational backgrounds, however data drawn from national representative surveys do not collect exact measures of alcohol intake that would permit to accurately assess self-report bias in different population groups. To our knowledge, there is no evidence on the distribution of the self-report bias by population group and how far self-reporting alcohol consumption may impact on social disparities in drinking.

This paper aims to assess the potential effect of correcting for self-report bias in alcohol consumption on social disparities. The study focuses on social disparities in HD using national health survey data from 13 OECD countries. It contributes to the existing research in two ways. First, it provides a summary index of inequality making cross-country comparison easier. Second, it proposes to correct alcohol consumption for self-reporting following Rehm s approach, 16 and to assess for the first time how correcting for selfreport bias may affect social disparities in drinking.

METHODS

Data

Data are gathered from national health surveys, or alcohol and drug use surveys, for 13 OECD countries: Canada, England, Finland, France, Germany, Hungary, Ireland, Japan, Korea, New Zealand, Spain, Switzerland, and the USA. They provide the most detailed information currently available on individual characteristics combined with drinking behaviours, either measured over the week prior to the interview in 5 countries (Canada, Finland, Hungary, Japan, and Switzerland) or based on frequency and quantity of alcohol consumed on a typical drinking day in the 8 remaining countries. Table 1 presents the list of surveys.

Table 1. List of data sources

Cross-country comparisons of drinking behaviours are challenging because of the lack of international consensus in the definition of a standard drink 16 and drinking limits. 26 In this study, the quantity of alcohol consumed (expressed in grams of pure alcohol per week) was derived from the number of standard drinks as defined in each country. Combining information on quantity and frequency of alcohol consumption permits to calculate quantity per week. People who did not consume alcohol in the past 12 months are considered as abstainers and are assigned 0 gram per week. HD threshold is defined as 140 grams of pure alcohol per week (or 2 drinks per day) for women and 210 grams per week (or 3 drinks per day) for men. This measure refers to the limits above which people are at risk for their health as defined in a number of countries. A common set of individual characteristics includes gender, age, ethnicity, marital status, working status, smoking, education level and socioeconomic status (SES) (occupationbased or income level) (further described in Annex 1). Since this study focuses on the relationship between education and HD, the analysis covers adults aged 25 and over, who have finished their education, in order to address endogeneity problems. It is worth noting that the maximum age is 65 in Germany and 75 in Finland due to inclusion criteria in surveys. All analyses use sampling weights. All analyses are undertaken with Stata 13.

Identifying within-country disparities

Logistic regressions are used to assess within-country disparities in HD by education level and SES while controlling for a range of covariates. Gender-specific regressions -as noted in equation [1]-are performed for each country. [1] where p is the probability of HD, age i denotes age of individual i, mar i marital status, eth i ethnicity (available in England, New Zealand and the US), smk i smoking, and wrk i working status. The education (edu i ) and SES (ses i ) variables are entered one by one, then together in the model. Adjusted probabilities by education level and SES are derived after fitting the statistical model. They represent the probability of being hazardous drinker for a typical man (or woman) aged 40 years-old and with all other covariates fixed at the sample mean (except education level and SES).

Measuring between-country disparities

To assess between-country disparities, it is necessary to use an aggregate index of inequality in order to take into account differences in the size and nature of socioeconomic groups in different countries. This stud uses the Wagstaff s concentration index (WCI) to quantify education-related and SES-related disparities. Calculation for WCI is described in Annex 1.

Correcting for self-reported alcohol consumption

Survey-based alcohol consumption is corrected to reflect the overall APC follo i g 'eh s ethod. 16 This approach aims to correct survey data using aggregate APC data by modelling the upshifted distribution of Social inequalities in health-related behaviours: Chapter 3 Is the grass greener on the other side? -117 -alcohol consumption. It relies on the assumption that the proportion of abstainers as measured in the survey is accurate because only drinkers can be adjusted, and that the alcohol consumption is gammadistributed. The procedure uses as a factor of correction the coverage rate of total alcohol consumption as measured in the survey data over the overall APC (Table 2)

RESULTS

Figure 1 shows the adjusted probabilities of HD in men and women by education level, all other things being equal. Corresponding results of social disparities by SES are displayed in Figure B1 in Annex 2.

Levels of HD are low, especially among women in France and Hungary. Men with more education tend to engage less in HD than their less-educated counterpart, although the gradient is seldom significant. This pattern (referred as negative gradient) is observed in 9 out of 13 countries and the gradient is significant -118 -in Korea only. Conversely, in Canada, England, Finland, and Germany, men with more education are more affected by HD, this gradient (referred as positive gradient) being significant in Germany only. The pattern for SES-related disparities is more mixed, with a positive gradient in 6 countries (significant in 3 countries) and a negative gradient in 7 countries (significant in Hungary only) (see Figure B1 in Annex 2). Regarding women, the prevalence of HD is lower than in men, and the pattern of inequality is clearer. The relationship between education level and HD is positive in 10 countries and significant in four of them (Canada, England, Germany and Switzerland) (Figure 1). Conversely, Japan, Korea and New Zealand display a negative relationship (significant in Korea). The pattern for SES-related inequalities is consistent, with 9 countries showing a significant positive gradient of inequality (see Figure B1 in Annex 2).

Figure 1. Adjusted probabilities of hazardous drinking by education level

Men Women

Note: * means that the overall gradient is significant at 5%. In England, the probability of HD for men aged 40 years-old and all other characteristics fixed at the sample mean, is equal to respectively 18%, 21% and 23% in the low, medium and high education groups.

Figure 2 displays the WCI for HD by education level, before and after correcting for self-report bias.

Before correction, in men, the pattern of inequality is mixed and its degree is generally small. Eight of the 13 studied countries present a positive index -indicating larger HD rates in men with lower education-, with Korea and the US showing the largest inequalities. In contrast, England and Germany show large degree of inequality in the reverse direction. Corresponding results by SES support these findings (see Figure B2 in Annex 2). For women, social disparities observed in 11 of 13 countries before correction suggest larger HD rates in women with higher education, with the largest inequalities in England and

France. In contrast, Korea and New Zealand show a reverse gradient, indicating that less educated Social inequalities in health-related behaviours:

Chapter 3 Is the grass greener on the other side?

-119 -women are more affected by HD. Results by SES confirm these findings, indicating larger inequalities in Canada and England (see Figure B2 in Annex 2). Comparison between genders shows a contrasting educational gradient in 7 countries (France, Hungary, Ireland, Japan, Spain, Switzerland, and USA), and similarly, a contrasting SES gradient in 6 countries (France, Hungary, Japan, Spain, Switzerland, and USA).

Changes after correcting for self-report bias

Differences in WCIs before and after correction are graphically displayed in Figure 2 and reported in Table B1 in Annex 2. In men, in countries where the WCI was initially negative (e.g. England), the correction leads to a steeper gradient. In countries where the WCI was initially positive, the correction results in smaller disparities (e.g. New-Zealand), or even a reverse gradient (e.g. France). The before/after correction difference in WCIs is negative in men in all countries, indicating that the correction leads to a greater relative increase in rates of HD in men with higher education/SES. In women, the difference in WCIs is negative in most countries, magnifying the size of social disparities. Even when the difference caused by the correction is positive, this does not reverse the sign of the social gradient.

-0.

DISCUSSION

This paper shows that men and women with more education or higher SES often differ in their propensity to engage in HD. Higher-educated women are more likely than the lower educated to drink at risk while the opposite is observed in men in most countries. The degree of inequality varies between countries since social patterns of drinking are largely the result of cultural and environmental influences, and of government policies in place in the countries concerned. Larger social disparities in women are found in Canada, England and France, whereas larger social disparities in men (though the male gradient is opposite) are found in Korea and Hungary. The effect of correcting for self-report bias is consistent across countries and leads to larger increases in HD rates in people with higher education/SES. After correction, social disparities increased in women, and decreased in men, to the point that gradients were reversed in several countries (from higher rates in men with low education/SES to a reverse pattern).

Interpretation of findings

The negative relationship between SES and HD, frequently observed in men before correction, is in line with most findings on inequalities in unhealthy lifestyle habits (e.g. smoking, obesity), with a range of explanations including health information, time preferences, and intergenerational transmissions.

Environmental factors may also contribute to explaining this gradient since higher alcohol outlets density -associated with greater levels of alcohol consumption- 27-28 is apparent in more disadvantaged urban areas in New Zealand and the United States. 29-30 Conversely, the positive association between SES and HD largely observed in women and in both genders after correction, differs from the usual gradient in unhealthy lifestyle behaviours, confirming previous results. 31-32 Possible explanations for this g adie t i lude i di idual s afflue e, possi le ill-health, ha ge i o e s so ial positio , a d so ial o s. Fi st, i di idual s afflue e a d al ohol p i es a e important determinants of consumption. People with higher SES, and thus with higher incomes, tend to consume more alcohol and more frequently since they can afford it, although this is not consistently related with engaging in HD. 5 Second, people in lower-SES may consume less alcohol because of poorer health. This assumption was tested by adding controls for self-assessed health in the model. Results show that the coefficients associated to education and SES remain significant although slightly attenuated, suggesting that, for a given health status, disparities in HD across social groups persist. Third, the link between higher SES and higher propensity of HD is more often observed in women, contrary to men, Social inequalities in health-related behaviours:

Chapter 3 Is the grass greener on the other side?

-121 -possibly related to ha ges i o e s o upatio al status a d positio . Wo e ith highe edu atio who end up taking better-paid jobs involving higher degrees of responsibility may drink more heavily because they have more stress and more frequent occasions of socializing and going out with colleagues compared to their low-SES counterpart. Besides, these occasions being typically in masculine work environment, women are confronted to higher limits of drinking. 33 This assumption was tested on French data by disentangling women in high socioeconomic position in masculine work environment (in managerial /technical occupations) versus women in high socioeconomic position in less-masculine environment (in teaching /arts / health occupations). Findings confirmed that women in masculine work environment are more likely to drink heavily compared to women in less-masculine work environment.

Finally, change in social norms may be analysed through the theory of social innovation diffusion suggesting that high-income people first appropriate innovative goods or behaviours -such as new drinking patterns-in a way to distinguish from other social groups. 34 After some time, the innovation spreads to all other population groups. In a second stage, once HD behaviour is common in all population groups and as the associated risks for health are spread, high-income people first start to stop HD.

Generally, a time lag is observed between men and women -like for smoking some decades ago. 35 Adoption of HD o e to i itate e s eha iou s a e see as g eate ge de e uit . 36 Under this assumption, our results suggest that in most countries men are in the second phase of the social innovation diffusion whereas women are in the first stage, and that female social disparities will resemble male disparities in the future.

Regarding self-report bias, this study showed that alcohol consumption estimated from survey data covers between 16 and 67% of the alcohol volume derived from aggregate sales data. These figures are consistent with previous reports, 13-14,37 and cast doubt on the reliability of alcohol consumption estimates from self-reported survey data. Finally, our correction for self-report bias resulted in larger increases in HD rates in people with higher education/SES. This can be explained by the fact that low-SES people are more often abstainers than high-SES people, and, since the correction is applied only to drinkers, more high-SES people than low-SES people end up crossing the HD threshold after correction. This clearly assumes that the higher prevalence of abstinence in people with lower education/SES reported in surveys can be trusted. In fact, this is supported by evidence based on purchase data, indicating that fewer low-SES than high-SES households purchase alcohol. 38 Our finding also raises questions on differences in the knowledge of drinking limit guidelines between SES groups. High-SES people may be better informed about these guidelines, and so, may more frequently report an average alcohol consumption just below the limit, explaining why they are more often crossing the HD threshold after correction.

Possible limitations

This study presents some limitations. First, comparability of results is limited due to the use of different national surveys that may be a source of data heterogeneity. Data are gathered from different national surveys, supposing differences in survey methodology, sampling, and questionnaires. Although lot of efforts was made to get the highest level of comparability across countries, some differences remain as indicated in the Methods section. Second, participation rate regarding questions on drinking is especially low in a number of countries. Survey design and questions formulation have an influence on quality of responses. As a consequence, results may be affected to different extents across countries. Third, the time span of five years in the study may be a source of limitation for comparison over time. Survey data from 2006 to 2011 were put together although the economic crisis and its impacts on job market may have influenced drinking behaviours. Fourth, the correction for self-report bias does not account for differences by socioeconomic group. Additional sources of information combining self-reported consumption and alcohol purchase or alcohol intake diary, stratified by socioeconomic group, would be useful although this type of data is not commonly available. Despite these limitations, this study gives some insights into differences in HD across population groups in 13 countries, and it assesses for the first time the potential effect of correcting for self-report bias on social disparities. This paper contributes to a better knowledge of the social dimensions of alcohol drinking and to the targeting of alcohol policies. It permits to identify the population groups the most at risk of HD and reveals gender differences in socioeconomic disparities. More importantly, this paper highlights large discrepancies in alcohol consumption between survey-based and aggregate data, and it suggests that neglecting self-report bias may lead to incorrect estimates of social disparities in HD.

ANNEXES Annex 1 -Methods

Data description

Ethnicity is reported in England, New Zealand, and the US. France, Hungary, Japan, Spain, and Switzerland. In countries for which an occupation-based SES variable could not be derived, household income was instead used as an indicator of SES. These include Canada, Finland, Germany, Ireland, Korea, New Zealand, and the USA. Data description and comparability are available on demand.

Measuring between-country disparities

The concentration index (CI) assesses the correlation between the individual's hazardous drinking status and the individual's ranking in the distribution of education level (and SES, respectively -128 -the CI are robust to heteroskedasticity and autocorrelation (Kakwani, Wagstaff, & Van Doorslaer, 1997).

For binary health outcomes, the bounds of the CI depend on the minimum, the maximum and the mean of the health variable. This is potentially problematic for international comparisons when the prevalence of the health outcome varies across countries. To take account of this issue, Wagstaff (2005) and Erreygers (2009) proposed modified versions of the CI for binary outcomes. We present in this paper the Wagstaff s i de defi ed as:

μ he e μ is the eighted ea of the health out o e.

The WCI is bounded between -1 and 1, with the sign indicating the direction of inequality -a positive index indicates that people with less education or lower SES are more likely to be hazardous drinkers, a zero value indicates no inequality, and a negative index indicates that people with more education or higher SES are more likely to be hazardous drinkers. It is worth noting that when zero inequality occurs, it may hide that, for example, inequality favouring the worst-off in one part of the distribution exactly offsets inequality favouring the best-off in another. The concentration index and its standard error are computed with the Stata concindc command for the micro-data with a categorical welfare variable [START_REF] Chen | CONCINDC: Stata module to calculate concentration index with both individual and grouped data[END_REF].

Correcting for self-reported alcohol consumption

The o e ted ea μ i a d sta da d de iatio σ i ) of the shifted distribution are defined as follows:

where m i is the weighted sample mean in group i and r the coverage rate.

for men and for women, where the multiplicative constants are empirically derived from international data [START_REF] Kehoe | Determining the best population-level alcohol consumption model and its impact on estimates of alcohol-attributable harms[END_REF].

This approach assumes that the shifted alcohol distribution for each gender and age group i has a gamma -129 -they are attributed the same percentile rank. Once the correction is applied, individuals are assigned a new corrected HD status. We then compute the new WCI after correction.

As a result of the correction, the cumulative distribution of alcohol consumption is shifted to the right, indicating higher levels of consumption (see Figure A1). After correction, the quantity of alcohol drunk per week increases to various extent by level of drinking: by 26g in mild 17 drinkers, 188g in moderate drinkers, and 760g in hazardous drinkers in men (respectively, 16g, 109g and 387g in women) on average in all countries. The size of the correction is by construction larger for the heaviest drinkers, this assumption being supported by previous findings showing larger self-report bias in heavy drinkers (Townshend & Dukat, 2002;Lemmens, Knibbe, & Tan, 1988;Zhao, Stockwell, & Macdonald, 2009;Studer, et al., 2013).

INTRODUCTION

Most OECD countries have endorsed as major policy objectives the reduction of inequalities in health status and the principle of adequate or equal access to health care based on need. Equity of access is a key element of health system performance in OECD countries [1,2].

Effective health care coverage provides financial security against expenses due to unexpected or serious illness, and promotes access to medical goods and services. Most OECD countries have achieved universal, or near-universal coverage of their populations for a core set of health care services. Access to doctor services is ensured at relatively low or no cost for patients. Other services such as dental care and pharmaceutical drugs are often partially covered, although there are a number of countries where coverage for these services must be purchased separately [3]. Preventive screening services for certain cancers such as breast and cervical cancer are generally also available at little or no cost. However, despite these health system features, the utilisation of health care services has been shown to be unevenly distributed across population groups [4][5][6][7][8][9][10][11].

There is already a substantial body of evidence for many countries that inequities -i.e. inequalities remaining after adjusting for needs for health care-exist in the use of certain health care services.

Previous research on OECD countries in the early 2000s showed that the better-off were more likely to see a medical specialist, and they often visited these specialists more frequently [4,5]. Dental care was also used more often by the better-off whereas the picture for general practitioner (GP) visits was less clear-cut with some evidence for pro-poor inequities. Likewise, European studies using data around the year 2000 confirmed these patterns [6,7]. Since that time, several countries have introduced policy measures. In particular, one can think of the introduction of a free complementary health insurance coverage for low-income people (called CMU-C) in France in 2000, the extension of public-funded dental care coverage to the whole population in Finland in 2002, the increase in GPs supply in deprived areas in England after 2002, the introduction of gatekeeping in Germany in 2004, or the recent implementation of public screening programmes in a number of OECD countries. These new features may have modified access to care and thus it is of interest to re-examine inequalities in health care services utilisation (HCSU) to assess the effectiveness of policy outcomes.

Social inequalities in health-related behaviours: Chapter 4 Is the grass greener on the other side? -136 -Moreover, although an increasing number of studies pay attention to inequalities in the use of preventive care in the international context [8,9], to our knowledge, only two studies have focused on gauging these inequalities. The first one covers income-related inequalities in cervical cancer screening in 67 countries (mainly developing countries) [10], and the second one measures inequalities in preventive care treatment in European countries [11]. Our study contributes to this research focusing on both breast and cervical cancer screening and covering a broader set of countries.

This paper aims to re-examine income-related inequalities and inequities in HCSU in 18 OECD countries with 200618 OECD countries with -2009 data. It updates previous results for 12 countries from the van Doorslaer and Masseria study [5], and covers six new countries (including New Zealand and five Eastern European countries). The range of health care services includes doctor and dentist visits, and is extended to breast and cervical cancer screening. This paper contains four sections. After the preceding Introduction, Section 2 describes the data and methods used to measure income-related inequalities and inequities in HCSU. Section 3 presents results among 18 OECD countries. Section 4 provides a discussion of findings and concludes the paper.

DATA AND METHODS

Data on HCSU were taken from national health surveys of 18 selected OECD countries. For most European countries, these came from the European Health Interview Survey (EHIS), which was implemented across countries between 2006 and 2009. For other countries, the most recent national health surveys were used (see Table 1). Although the use of different national surveys for several years might be a source of data heterogeneity across countries, all the variables were constructed in order to get the highest level of comparability. -140 -

Measuring inequalities

The concentration index (CI) is used to quantify the degree of inequality of actual medical care utilisation related to income level by assessing the o elatio et ee the i di idual s HC"U a d the i di idual s ranking in the income distribution. The CI of a health variable Y can be computed using the simple convenient covariance formula [START_REF] Meier | Adjusting for unrecorded consumption in survey and per capita sales data: Quantification of impact on gender-and age-specific alcohol-attributable fractions for oral and pharyngeal cancers in Great Britain[END_REF]: he e μ is the eighted sa ple ea of Y, o w denotes the weighted covariance and R i is the relative fractional rank of the ith individual in the income distribution. The standard errors computed for the CI are robust to heteroskedasticity and autocorrelation [START_REF] Rehm | Statistical modeling of volume of alcohol exposure for epidemiological studies of population health: the US example[END_REF]. The CI permits to gauge relative inequalities i.e. a positive index indicates pro-rich inequality, a negative index pro-poor inequality, and a zero value no inequality. The more the HCSU is concentrated on the most advantaged (most disadvantaged) groups, the higher (lower) is the value of the CI. If HCSU is equally distributed among socioeconomic groups, then the CI is equal to zero. However, for binary health outcomes, the bounds of the CI depend on the minimum, the maximum and the mean of the health variable. This is potentially problematic for international comparisons when the prevalence of the health outcome varies across countries. To take account of this issue, Wagstaff (2005) and Erreygers (2009) proposed a corrected version of the CI for binary outcomes [START_REF] Ely | Methods of estimating individual levels of alcohol consumption in the general population[END_REF][START_REF] Midanik | The Validity of Self-Reported Alcohol Consumption and Alcohol Problems: A Literature Review[END_REF]. We present in this pape the Wagstaff s i de defi ed as: where μ is the eighted ea of the health outcome 20 . All analyses use sampling weights. This paper deals with the two concepts of inequalities and inequities in HCSU as defined above. In the follo i g se tio s, the te i e uit efe s to i e ualit fo eed-adjusted HCSU -i.e. for doctor, GP and specialist visits-he eas the te i e ualit is e plo ed fo de tist isits a d a e s ee i g uptake, not adjusted for health care needs. 20 The analysis was also carried out with the Erreygers index. Results were broadly similar.

Social inequalities in health-related behaviours:

Chapter 4 Is the grass greener on the other side? -141 -

National health system characteristics

The 18 countries studied in this analysis have different health system characteristics that may affect inequalities and inequities in HCSU. At the time of the data collection -around 2006-2009-most of these countries have achieved universal health coverage for their population except USA. The share of public and private health financing (including private insurance and out-of-pocket payment) varies across countries, with a large share of private financing in Hungary, Switzerland, and USA. The share of out-ofpocket payments as percentage of expenditure in dental care measures the financial burden for households; it shows variations from 42% in Germany to 98% in Spain. Cost-sharing arrangements for do to s isits -like free care at the point of delivery in Austria, Canada, Germany, Poland, Spain and UKare likely to influence equity in access to health care. Countries with strengthened primary care organisation and gatekeeping system may provide simpler access and better guidance for people in lower socio-economic positions. -143 -The gatekeeping system is in place in Estonia, Slovak Republic, Slovenia, Spain and USA, through a compulsory registration to a primary care physician and a required referral to access specialist care.

Organisational features such as the type of health care provision -mostly private in 11 countries-and the existence of public screening programmes may also play a role on access to care. Free nationwide population-based screening mammography programmes operate in 2010 in Belgium, Czech Republic, Finland, France, Germany, Ireland, New Zealand, Poland, Spain, and UK (not nationwide in most of other countries). Pap smear tests are available through free nationwide population-based programmes in Czech Republic, Finland, Germany, Hungary, Ireland, New Zealand, Poland, Slovenia, and UK 21 . Data on health system characteristics presented in Table 2 refer to the years 2008 to 2012 and come from OECD data sources [START_REF] Stockwell | Under-reporting of alcohol consumption in household surveys: A comparison of quantity-frequency, graduated-frequency, and recent recall[END_REF][START_REF] Hill-Mcmanus | Estimation of usual occasion-based individual drinking patterns using diary survey data[END_REF]20]. We refer to these cross-country differences when interpreting the study findings.

RESULTS

Inequities in need-adjusted doctor visits

Figure 1 shows income-related inequities in the probability of a doctor visit after adjusting for i di iduals eeds fo health a e. The i e uit i de is sig ifi a tl greater than zero in 14 out of 16 countries, indicating that for the same level of needs for health care, people with higher incomes are significantly more likely to visit a doctor than those with lower incomes. The magnitude of these inequities varies among countries, USA displaying the largest inequities followed by France, Poland, and Canada. In contrast, Slovak Republic, Spain and Switzerland show a lower degree of inequities.

At the other end of the spectrum, UK presents an inequity index which is not statistically different from zero, indicating that no inequities can be detected. This is also the case for Czech Republic although the small sample size in Czech Republic limits the ability to detect significant effects. The degree of inequity is the highest in USA, where the universal health primary coverage was not achieved. Beyond primary coverage, the role of private health insurance is of importance. USA, France, and Canada which present large inequities, are characterised by large share of private insurance expenditure (as shown in Table 2). Larger inequities are found in countries where the provision of care is predominantly private (USA, France, Poland, Canada, Estonia, and Belgium) although this is also true in Czech and Slovak Republics, Switzerland and Germany. Virtually no Social inequalities in health-related behaviours: Chapter 4 Is the grass greener on the other side?

-144 -inequity is found in UK where outpatient primary and specialist care is free of charge at the point of delivery. Similar settings are in place in Spain and Germany 22 where inequalities are small, but also, in Canada and Poland where inequities are larger, suggesting that other features may influence inequities in doctor visits.

Figure 1.

Inequity index for the need-adjusted probability of a doctor visit and its 95% confidence intervals

Inequities in need-adjusted GP and specialist visits

Figure 2 presents income-elated i e uities i GP a d spe ialist isits afte adjusti g fo i di iduals needs for health care. Nine out of 16 countries display significant inequities in GP visits (Figure 2, Panel A). The largest inequities are observed in Canada, Poland, and New Zealand. Conversely, seven countries present no significant inequities, indicating that people with lower incomes are as likely as those with higher incomes to consult a GP. Germany and USA do not present data split by GP and specialist. The largest inequities in GP visits are found in New Zealand where the average costsharing for an outpatient primary care physician contact is about 30%, with a range of copayments depending on practice type and patient status. In contrast, smaller inequities are observed in countries providing free care at the point of delivery (Spain, Austria, and UK) or with a small copayment of about 1 euro per visit (Czech Republic and Hungary).

22 For people with statutory health insurance.

-0. The variation of inequities in specialist visits among countries (Figure 2 Panel B) is larger than that of inequities in GP visits, and the pattern is also clearer. In all countries -but two-the inequity index is significantly greater than zero, which means that for the same needs for health care, people with higher incomes visit specialists more often than those with lower incomes. In particular, France and Spain display the largest inequities. On the other hand, no inequities can be detected in UK (and in Czech Republic due to the small sample size) and low degrees of inequities are found in Slovak Republic, New Zealand 23 , and Slovenia. These three countries as well as UK are characterised by the fact that GPs act as gatekeepers and a referral is required to get access to specialist care. However, this is also true in Spain which has the second highest degree of inequities in specialist visits. Beyond that, the distinction between public and private sectors has its importance since inequities in specialist visits in Spain were found mainly in the private sector [START_REF] Ekholm | Influence of the recall period on self-reported alcohol intake[END_REF].

Inequalities in dentist visits

Figure 3 shows that all countries display significant income-related inequalities in dental visits. The extent of these inequalities varies greatly among countries. Canada and USA stand out with the strongest inequalities that are more than three times the degree of inequalities observed in Switzerland. The two countries with the strongest degrees of inequality are characterised by a large 23 In New Zealand, specialist visits in contrast with GP visits are exempted from copayments -146 -share of private expenditure for dental care (95% in Canada and 91% in USA). This is also true in Spain (99%), France (64%), and Poland (64%) where inequalities in dentist visits are large. However, Switzerland also presents a high share of private expenditure for dental care (93%) but has the lowest level of inequality. This suggests that other institutional factors play a role on inequalities in the use of dental care such as exemptions of copayments for certain groups of population. Inequalities in breast cancer screening in favour of the better-off are shown in 12 out of 16 countries. The largest inequalities are observed in Belgium, Estonia, France, and USA. In contrast, no inequalities can be detected in four countries (Czech Republic 24 , Slovak Republic, Slovenia, and UK).

Inequalities in cancer screening

Inequalities in cervical cancer screening are shown in all countries but two. The degree of these inequalities varies from below 0.10 in Ireland, Slovak Republic, Slovenia, and Switzerland to more than 0.20 in Belgium, Czech Republic, and France.

Inequality in cancer screening must be interpreted with regards to the level of cancer screening rates (displayed in Table 1). Breast cancer screening rates are high in Austria, France, New Zealand, Spain, and USA, with more than 75% of women aged 50-69 years having a mammogram in the past 2 years.

At the other end of the spectrum, in Estonia, only 36% of women had a mammogram in the past 2 years. Similarly, cervical cancer screening rates are high in USA, Austria, Spain, Slovenia, and Canada, 24 The small sample size in Czech Republic and Slovenia prevents from detecting significant differences. -147 -with more than 75% of women aged 20-69 years having a Pap smear test in the past 3 years, whereas this proportion is only 34% in Switzerland. The Wagstaff index used in this study already makes the adjustment for differences in the national average rate of screening, giving a higher weight to the countries with larger screening coverage. A country with a small degree of inequality and a wide screening coverage may count as much as a country with large inequalities and a small population coverage. This is the case for instance in Estonia and Belgium. Estonia has a large degree of inequality in breast cancer screening (crude CI=0.17) but a small proportion of screening uptake (36%). In comparison, Belgium has a smaller degree of inequality (crude CI=0.08) and a larger screening rate (74%). After adjustment for the level of screening rate, the Wagstaff inequality indexes are respectively 0.27 in Estonia and 0.30 in Belgium. The utilisation of cancer screening services may largely depend on the availability of national public screening programmes. For instance, recent findings in the European region highlight that inequalities are larger in countries without a population-based screening programme [8]. In our study, the degree on inequalities in cancer screening has been examined in the light of the existence of national screening programmes, however we do not find any clear association. Beyond the existence of screening programmes, the lack of association may be related to the time since programmes were rolled out. Another explanation relies on the fact that screening is often fully covered by insurance in most countries [22,20]. This corroborates a recent study showing that the impact of the availability of national programmes on screening uptake is mediated to a minor extent by solving financial restriction, and to a large extent by preventing women from considering screening not necessary [23].

- -148 -Reasons for cancer screening uptake depend not only on national institutional features but also on individual characteristics. Ethnicity, younger age, higher education level, employment status, residential area, marital status, having health insurance, good health status, having an usual source of care and use of other preventative services, are all recognized as important additional predictors of participation in screening. For instance, in the United States, low-income women, women who are uninsured or receiving Medicaid (health insurance coverage for the poor, disabled or impoverished elderly), or women with lower educational levels report much lower use of mammography and pap smears [24]. Similarly, in European countries, significant inequalities related to education and socioeconomic status are found in the utilisation of early detection and preventive health care services [25,26].

DISCUSSION AND CONCLUSIONS

Since inequities in HCSU were first assessed across OECD countries around the year 2000, governments have prioritised equity of access and made health system features evolved. This study shows that a decade later, income-related inequalities and inequities in HCSU remain existent in OECD countries. In the majority of countries, for the same needs for health care, people with higher incomes are more likely to consult a doctor -in particular, a specialist-than their counterpart with lower incomes. Inequalities in dental and preventive care are also found in most countries, if not all.

The magnitude of these inequalities varies considerably among countries. Results show larger inequalities in France and USA. In particular, USA present the strongest inequalities in doctor and dentist visits. France displays the largest inequalities in specialist visits and among the largest inequalities in doctor visits and cancer screening. On the other hand, inequalities are generally smaller in Switzerland (notably in dental and preventive care) and UK (in doctor and specialist visits, and breast cancer screening).

These results are consistent with the literature [4][5][6][7]. Recent findings on European data highlight that inequities in specialist visits are the highest in France and Spain [6,8]. Regarding dental care services, inequalities in favour of the better-off are found consistently in a large number of countries [27].

Part of cross-country discrepancies finds some explanations in the differences in health system characteristics. In particular, larger inequities are found in countries where: universal health Social inequalities in health-related behaviours: Chapter 4 Is the grass greener on the other side?

-149 -coverage is not achieved, health care financing relies on a large share of private insurance and outof-pocket payments, GPs do not act as gatekeepers, health care provision is mostly private and national cost-sharing arrangement does not include free care at the point of delivery.

Comparisons with the previous study around the year 2000 [5] cannot be directly made because different types of index were employed, our study using the Wagstaff index, a more appropriate index for international comparisons. Results obtained with the exact same methodology as the one previously used (not displayed herein) suggest that overall, inequities and inequalities have remained stable over time, despite few exceptions. The country ranking and the size of inequities are reasonably consistent, especially for doctor and GP visits. Some differences in surveys and in wording of questions may affect comparisons, in particular for specialist visits in Finland and France, and for dentist visits in Ireland and Spain, but only to a less extent (detailed results available in [28]).

Comparisons over time could be undertaken with more rigorous techniques like the Oaxaca-type decomposition of change in CI [29]. However, this requires to access and to harmonise survey data of several past years. This was not in the scope of this study but it could be performed in future developments.

This study offers new information on income-related inequalities in HCSU and it presents, for the first time, a cross-country comparison of the degree of inequalities in breast and cervical cancer screening. However, this paper has several limitations. First, this study could not separate public from private health care services whereas some evidence suggests that different patterns exist.

Inequities in specialist visits are shown to occur largely in the private sector in Spain, while the public health system is more equitable [START_REF] Ekholm | Influence of the recall period on self-reported alcohol intake[END_REF]. Similarly, inequalities in dental care utilisation are found to vary between public and private services in Finland [30]. Second, this study considers dental visits as a whole since the data does not permit to distinguish curative and preventive dental care. However results may differ across both types of care, preventive dental care being associated with larger inequalities [27,31]. A third limitation is related to the appropriateness of the definition of health care needs. In this study, health care needs include the self-assessed health status which is widely regarded as a good predictor of both health care utilisation and mortality [START_REF] Van Kippersluis | al ool e F a e: uelles so t les populations à risque ? IRDES Questio d'Éco o ie de la Santé 129[END_REF]33]. Health care needs also include objective health indicators like the limitations in daily activities. Health care needs do not include any measure of morbidity although this adjustment was shown to have its advantages [START_REF] Bago D U A | Education-related inequity in healthcare with heterogeneous reporting of health[END_REF]. Morbidity as reported in national health surveys is subject to a high heterogeneity in individual responses. For instance, people who report chronic diseases are more likely to be those with sufficient health information, being in contact with doctors, and potentially with higher incomes. The Social inequalities in health-related behaviours: Chapter 4 Is the grass greener on the other side? -150 -adjustment for morbidity as reported in surveys may thus bias the measurement of socioeconomic inequalities in health [START_REF] Tubeuf | Social Heterogeneity in Self-Reported Health Status and Measurement of Inequalities in Health[END_REF]. Recently, methodological improvements show that assuming homogeneity in the relationship between need and use of care tends to underestimate pro-rich inequity [START_REF] Van De Poel | Measu e e t of i e uit i health a e ith heterogeneous response of use to need[END_REF]. These further improvements could be applied in future studies once the limitations of objective health measures have been handled. Last, the income variable was derived on the basis of the survey data available. A lot of effort was made to equivalise household income and to get data harmonised across countries despite differences and limitations in data sources. A sensitivity analysis for the use of income confirms the robustness of our findings. We replicated the analysis by using (not equivalised) household income and found consistent results. This paper suggests that further monitoring of inequalities in HCSU is essential in order to assess whether country policy objectives are achieved on a regular basis. The findings highlight that inequalities and inequities in HCSU have remained present over time in the studied period in OECD countries despite developments of health care systems. However, more recent reforms are expected to lead to changes in access to care, like the extension of the primary health coverage in USA, the introduction of exemptions of copayments and up-front payments for vulnerable populations visiting GPs in Belgium in 2011, and the suppression of copayments for GP and specialist visits in Germany in January 2013. Future studies could examine the impact of these specific health reforms on equity in health care access.

General Conclusion

Social inequalities in health-related behaviours:

General Conclusion

Is the grass greener on the other side? -156 -

Summary of key findings

This thesis aims to analyse social inequalities in health-related behaviours from an international perspective. This work is composed of four chapters which relate to three inequalitiesrelated issues: (i) addressing the challenges of measuring social inequalities in health-related behaviours using survey data for several different countries; (ii) shedding light on possible explanations of these inequalities, in particular by investigating the direction of the causal relationship, and also by examining the policy context; (iii) exploring how self-reporting may affect the measure of social inequalities. While the first chapter is an overview of data and methods, the last three chapters comprise articles that were published in economic or public health journals.

The first chapter of this thesis deals with the data and methods used in the different pieces of work presented herein. Health survey data for 23 OECD countries are described. Methodology for the measurement of social inequalities in health is presented and discussed, with a particular emphasis on the concentration index, and the absolute and relative indices.

The second chapter examines the size and the direction of the social gradient in obesity and overweight in 11 OECD countries. Education-related and SES-related disparities are measured by the means of the absolute and relative indices. Findings show that both absolute and relative inequalities need to be assessed since they may capture different dimensions and therefore lead to different country ranking. For instance, regarding education-related inequalities, absolute inequalities are largest in Hungary and Spain for both genders, whereas relative inequalities are largest in France and Sweden for men and in Spain and Korea for women. This study also shows that social inequalities in obesity and overweight are more marked in women than in men. The gender gap in social disparities in obesity is of great importance since women with low levels of education and low socioeconomic status (SES) are more likely to be obese and to give birth and raise obese children, thus perpetuating the vicious circle of social inequalities. Therefore, this paper is in support of policies aimed at targeting specific groups such as low-educated and low-SES women.

In addition to this paper, the second chapter presents an analysis that further explores the relationship between education and obesity, with the aim of understanding the nature of the link and the potential causal direction. The findings show a broadly linear relationship between the number of years of education and the probability of obesity, suggesting that increasing education at any point along that spectrum would reduce obesity to a similar degree, if the causal link between education and obesity had been established. However the causality between education and obesity Social inequalities in health-related behaviours:

General Conclusion

Is the grass greener on the other side? -157 -was not proven with certainty. Results from French data show that the strength of the association between education and obesity is virtually unaffected when controlling for reduced educational opportunities for those who are obese in young age, suggesting that the direction of causality runs mostly from education to obesity. Mo eo e , the a al sis of ediatio effe t ia the i di idual s socioeconomic status and the analysis of concurrent effect via education of household members show that education affect obesity essentially directly. Last, results highlight not only an absolute effect of the education level on obesity, but also a relative effect, i.e. the i di idual s edu atio le el relative to the pee s edu atio le el has a i flue e o o esit . In terms of policy implications, this study is in favour of further investment in education to help reduce obesity, via increased formal schooling and health education programmes, notably directed at the disadvantaged people who leave school early.

The third chapter deals with another behavioural risk factor for health: hazardous alcohol consumption. This analysis presents social disparities in hazardous drinking as reported in health surveys, and aims to assess the effect of self-report bias on social inequalities by correcting the distribution of self-reported alcohol consumption using alcohol sales data. First, findings show that the gradient of social disparities in hazardous drinking differs between men and women. Men with lower education levels and lower SES are more likely to engage in hazardous drinking compared to their counterparts with higher education levels and higher SES, whereas the reverse relationship is observed in women. Second, self-report bias tends to mis-estimate social inequalities in hazardous drinking. Correcting for self-report bias increases estimates of social disparities in women, and decreases them in men, to the point that gradients are reversed in several countries. This paper thus suggests that policies must target at-risk population groups, but more essentially, that further refinements in survey techniques need to be undertaken in order to correctly assess and monitor risky drinking behaviours at the individual level.

The fourth paper assesses income-related inequities in health care services in 18 OECD countries, and investigates potential determinants of these inequalities at the national level. Health care services that are examined include: doctor visits (including general practitioner and specialist), dentist visits, and cancer screening. The magnitude of inequalities is measured by means of a concentration index corrected to take account of the cross-country variation in the prevalence of the studied health outcome. Findings show pro-rich inequities in doctor visits (strongly marked in specialist visits), as well as in dentist visits and cancer screening uptake. Although the investigation of the correlation with national characteristics was limited by the data, some relevant insights Social inequalities in health-related behaviours:

General Conclusion

Is the grass greener on the other side? -158 -emerged. Larger inequities were found in countries where: universal health coverage is not achieved, health care financing relies on a large share of private insurance and out-of-pocket payments, GPs do not act as gatekeepers, health care provision is mostly private, and national costsharing arrangements do not include free care at the point of delivery. Regarding policy implications, this paper shows that despite national objectives of equity in health care access, inequities related to level of income persist. Results suggest some possible avenues of health system reforms that may help to achieve equity in access to care, and they suggest that further monitoring of inequities in health care services utilisation is essential to assess the success of future policies.

Recommendations for research and policy implications

The findings presented in this thesis have important policy implications and support a number of recommendations for future research. Two main recommendations for research may be drawn from this work. First, this thesis highlights a number of limitations regarding data harmonisation and data availability. Further improvements need to be made at the international level to carry out surveys with harmonised questions for the sake of international comparisons, and to make data available in a timely manner to researchers. Second, while researchers and experts already pay attention to measuring and monitoring health inequalities, more efforts need to be undertaken regarding the understanding of inequalities in order to design more effective policy instruments to tackle inequalities (e.g. identifying the causal impact of determinants on health inequalities).

Regarding policy implications, the findings presented in this thesis highlight possible policy levers to help reduce social inequalities in health-related behaviours, and more generally reduce social inequalities in health. First, this thesis provides some evidence that, in order to achieve effective policy measures, it is relevant to focus on the most at-risk population groups, in particular groups with lower education levels and lower socioeconomic status among which a higher prevalence of risk factors is concentrated, as well as lower income groups who experience higher barriers in access to care. Better-targeted redistributive policies (e.g. cash transfers, social safety nets) combined with health policy measures directed at the worst-off (e.g. health literacy or prevention programmes) could help to reduce inequalities in health-related behaviours.

Second, as shown in this thesis, health and health inequalities are related to a number of dimensions like education, employment and income. This means that from a policy viewpoint, it is Social inequalities in health-related behaviours:

General Conclusion

Is the grass greener on the other side? -159 -worth considering these multi-sectorial relationships, and thus, putting health policy at the centre of a broader policy agenda. One can think for instance, of including objectives for health outcomes in other policy sectors (like education, employment, and social affairs). For example, in Japan, a chronic disease prevention programme at the workplace is being developed with the aim of maintaining people longer in work and in good health, and as a result, improving work productivity. Of course, such initiatives imply coordination across ministries, and in particular, discussion of financing arrangements (e.g. who pays? who gets the return?).

Third, the framework of this thesis assumes that tackling social inequalities in health can be achieved to some extent by addressing inequalities in health-related behaviours. In particular, unhealthy lifestyles such as smoking, heavy drinking and obesity are directly targetable by governments to favour better health outcomes. Governments can reduce behavioural risk factors by implementing policies to reduce unhealthy lifestyles, such as health promotion and regulatory policies. Regarding health promotion policies to tackle obesity, coordinated national programmesincluding mass media campaigns and school-based interventions-are increasingly used by countries, such as the United States (Let's ove), the United Kingdom (Change4Life), and also amongst EU member states with the 2014 European action plan targeting childhood obesity. Beyond the sole role of governments, the involvement of multi-stakeholders like the tobacco, alcohol and food industries, the community, and patient and doctor associations, appears a promising strategy in order to achieve the best outcomes. For instance, food manufacturers can play a role in the fight against obesity by reformulating the contents of products, this is the case for instance in Hungary after the fat tax implementation, and in the Netherlands after the compulsory food labelling implementation. Regarding regulatory policies, governments can employ taxation, advertising regulation, and location and time restrictions (for smoking and drinking). For example, to counter obesity, France, Hungary and Mexico have used taxation for sugar-sweetened beverages. One concern about taxation is its regressive effect on low income groups. However, some analyses show that low-socioeconomic groups benefit more from prevention policies in terms of health outcomes since they have a higher prevalence of risk factors [START_REF] Sassi | Improving Lifestyles, Tackling Obesity: The Health and Economic Impact of Prevention Strategies[END_REF]. Moreover, to counterbalance the side effects of taxation, redistributive measures can be used. For instance, financial gains raised from taxes could subsidize vouchers for healthy products or baskets of fruits and vegetables to the low-income groups adversely affected by the introduction of such taxes.

Social inequalities in health-related behaviours:

General Conclusion

Is the grass greener on the other side? -160 -

Possible extensions of the work

Research presented in this thesis highlights the need for possible extensions of the work and raises further questions that could be addressed in future investigations. Four possible avenues of work development are proposed here.

First, the analysis of the relationship between education and obesity sheds some light on the nature of the link and attempts to explore the causality. However, the investigation of the causal relationship was limited because -at the time of analysis-cross-sectional data were only accessible whereas longitudinal data would have allowed assessment of causality. In order to expand this analysis, it would be worth exploring the causal link using longitudinal data such as the British Household Panel Survey, or the Household, Income and Labour Dynamics in Australia survey.

Second, the study on inequalities in hazardous drinking highlights important weaknesses of survey data regarding the measurement of alcohol consumption. Alcohol consumption is highly underestimated in health surveys. A correction of survey data from underreporting was applied by using national alcohol sales data. This work could be extended by considering another correction technique which combines various types of questions (the usual quantity-frequency questions and the consumption in the day prior to the interview) [START_REF] Meier | Adjusting for unrecorded consumption in survey and per capita sales data: Quantification of impact on gender-and age-specific alcohol-attributable fractions for oral and pharyngeal cancers in Great Britain[END_REF]Stockwell et al., 2014). This would allow confirmation of the findings on the mis-estimation of social inequalities in hazardous drinking due to the underreporting bias in alcohol surveys.

Third, the work on health care services utilisation tries to inform the role of national policy settings on social inequalities, although this analysis is strongly limited by the small number of countries 25 and so, by the lack of variability at the country level. More robust analyses (like multilevel modelling) could be undertaken in future work if access to adequate data sets to increase the number of countries was made possible.

Fourth, while the study on health care services utilisation highlights persistent income-related inequalities, it may be worth examining the effect of the 2008 economic crisis on health care utilisation and assessing to what extend the crisis has led to larger social inequalities in health care access. A recent study shows that the crisis has contributed to a deterioration in access to health care, although the effects may vary across European countries (Eurofound, 2013). Similarly, the latest European data (from EU-SILC 2012) indicates increased unmet care needs in the aftermath of the crisis among lower income groups (OECD, 2014). In the coming months, as new data are released, it will be possible to assess the impact of the crisis on the utilisation of health care services and on health outcomes by socioeconomic group.

Inégalités sociales des comportements de santé: L'herbe est-elle plus verte ailleurs?

Marion Devaux

Résumé : Cette thèse traite des inégalités sociales en matière de comportements de santé tels que les odes de ie li s à la sa t sp ifi ue e t, l o sit et la o so

  oeu e pou d eloppe des do es d e u te ha o is es au i eau Eu op e e . e u te ECHP European Community Household Panel, EHIS European Health Interview Survey, SHARE Survey of Health and Retirement in Europe). Alors que les gouvernements prêtent davantage attention aux inégalités de santé, des efforts techniques sont constamment développés au niveau international pour contrôler et comprendre ces inégalités. Par exemple, Eurostat inclut depuis peu un nouvel indicateur sur les

  diffi iles à esu e , leu esu e ta t e ta h e d e eu et de iais de d la atio . Pa e e ple, les esu es de l i di e de asse o po elle et d o sit peu e t t e sujettes à des i e a titudes dues à une d la atio e o es du poids et de la taille. De e, les esu es de o so atio d al ool peu e t souff i de iais d auto-déclaration avec une forte sous-esti atio de la ua tit d al ool o so e.

  Over the past 10 years, a lot of attention was paid to the determinants of health, notably under the WHO Commission on the Social Determinants of Health initiated in 2005. The work carried out by this Commission led to the publication of a main report in 2008: Closing the gap in a generation, followed by the 2011 Rio Political Declaration on Social Determinants of Health pledging to work towards reducing health inequities.

Figure 1 .

 1 Figure 1. Determinants of social inequalities in health

  Sabia S, Shipley M, Brunner E, Nabi H, Kivimaki M, Singh-Manoux A. (2010 , Association of socioeconomic position with health behaviors and mortality. The Whitehall II study . JAMA, 303(12): 1159-1166. T a o A, Tu euf ", Jusot F a d De au M, , I e uality of Opportunities in Health in France : a fi st pass . Health Economics, 19(8):921-38. Van der Pol M. (2011), Health, Edu atio a d Ti e P efe e e . Health Economics, 20:917-929. van Doo slae E, a d Kool a X. , E plai i g the diffe e es i i o e-related health inequalities a oss Eu opea ou t ies , Health Economics, 13: 609-628. a Doo slae E, a d Masse ia C. . I o e-related Inequality in the Use of Medical Care in 21 OECD Cou t ies . OECD Health Working Paper No.14. OECD, Paris. van Doorslaer E, Wagstaff A, Bleichrodt H, Calonge S, Gerdtham U, Gerfin M, Geurts J, Gross L, Häkkinen U, Leu R, O'Donnell O, Propper C, Puffer F, Rodriguez M, Sundberg G and Winkelhake O. (1997), "o ioe o o i i e ualities i health: so e i te atio al o pa iso s , Journal of Health Economics, 16(1): 93-112. a Kippe sluis H, a d Gala a T. , Wh the 'i h d i k Mo e ut s oke Less: The I pa t of Wealth o Health Beha io s . Tinbergen Institute Discussion Paper TI 2013-035/V. Wood a d A, a d Ka a hi I. , Wh edu e health i e ualities? J Epidemiol Community Health, 54:12 923-929.



  Heavy episodic drinking (HED), commonly called binge drinking, is collected in most of the national surveys through a question of the type: I the past o ths, ho ofte did ou ha e o o e d i ks o o e o asio ? he e = d i ks i Ca ada, Ge a , a d the U"; d i ks i Cze h

  breast and cervical cancer screening services for women. Both the probability and frequency of services were measured over the past 12 months. Typically, a first survey question assesses the probability of a isit, a d is of the fo : I the past o ths ha e ou isited a GP? . A se o d uestio easu es the frequency of visits in the past 12 months. For breast cancer screening, our focus was on women aged 50-69 years who reported having a mammogram in the past 2 years, and for cervical cancer screening, women aged 20-69 years who had a Pap smear in the past 3 years 7 .

  Gallup World Poll is conducted in around 140 countries around the world based on a common questionnaire, translated into the predominant languages in each country. With few exceptions, all samples are probability based and nationally representative of the resident population aged 15 and over in the entire country, including rural areas. Sample sizes are limited to approximately 1000 persons in each country. The survey is undertaken every year in most countries. Although this survey covers health-related issues, questions on medical visits, or data on Body Mass Index (including height and weight) are not included.  At the European level, three potential data sources were available for the purpose of this dissertation. The European Community Household Panel (ECHP) is a panel survey in which a sample of households and persons has been interviewed yearly. These interviews cover a wide range of topics: income, health, education, housing, demographics and employment characteristic, etc. The total duration of the ECHP was 8 years, running from 1994-2001. The use of ECHP was however rejected since the last survey edition was completed in 2001 and considered too dated for the purpose of our work.

Figure A1 .

 A1 Figure A1. Size of the BMI self-report bias by gender and ethnic background

Chapter 1

 1 Figure B1. Actual and corrected distribution of daily alcohol consumption

  correction: 12% of hazardous drinkers After correction: 32% of hazardous drinkers

Figure 1 .

 1 Figure 1. Example of calculation of RII and SII

Figure 1 .

 1 Figure 1. Absolute inequality indexes by education level

Figure 2 .Figure 3

 23 Figure 2. Relative inequality indexes by education level

Figure 3 .

 3 Figure 3. Absolute inequality indexes by socio-economic status

Figure 4 .

 4 Figure 4. Relative inequality indexes by socio-economic status

Figure A10 :

 A10 Figure A10: Trends in the US, in White population Panel A. Men Panel B. Women

  have shown much interest in the estimation of the causal effect of education on wages and economic growth (see Card 2001, for a comprehensive review of the literature) but only recently has work begun to investigate the non-monetary returns of schooling (see McMahon, 2004 for a review).Empirical studies, for example, suggest that education has a positive impact on health and well-being(Wolfe and Haveman 2002; Lleras-Muney 2005), particularly in poorer countries[START_REF] Cutler | Education and Health: Evaluating Theories and Evidence[END_REF], reduces crime (Lochner and Moretti 2004) and water and air pollution(Appiah and McMahon 2002). The finding that education has positive externalities provides a rationale for government intervention.

  a)to explore the correlation between body mass index, and obesity, on one hand, and formal education, expressed in terms of years spent in full-time education, on the other, controlling for possible confounding factors. The main goal of this analysis is to determine whether the intensity of the relationship between education and obesity is constant, or whether it shows increasing or decreasing strength at either end of the education spectrum. b) to assess the extent to which the correlations identified may reflect the influences of factors associated with individual education, such as socio-economic status and the level of education of household members. c) to assess the extent to which the correlations identified may reflect causal links between education and obesity. d) to explore what conceptual model of the role of education as a determinant of health is most consistently supported by the findings concerning the correlation between obesity and aspects of individual and group education. BOX 1: Data description The analyses reported in this paper are based on individual-level national health surveys covering four OECD countries: Australia, Canada, England and Korea. Data sources include the Australian National Health Survey (NHS) 1989-2005, the Canadian National Population Health Surveycross-section (NPHS) and the Canadian Community Health Survey (CCHS) 1995 -2005, the Health Survey for England (HSE) 1991-2005 and the Korean National Health and Nutrition Examination Survey (KNHANES) 1998-2005. All available survey waves were pooled for each survey. Since the focus of the analyses was the relationship between obesity and education, survey samples were restricted to individuals in the age range 25-64 who were supposed to have completed their full time education, and for whom the body mass index is a useful proxy for health risk. Body mass index (BMI) was calculated as weight in kilograms divided by square height in meters. Obesity and overweight status were then derived as BMI greater than 30 and 25.

  Is the grass greener on the other side? -71 -Australia has developed National Goals for Schooling in the Twenty-First Century, to which authorities across governmental jurisdictions refer to provide young Australians with the best possible educational outcomes and improve the quality of schooling nationally. The Active School Curriculum/ Building a Healthy Active Australia through the Department of Health and Ageing aims to provide young people with the skills to embrace an active lifestyle by introducing them to a range of physical activities. All state and territory governments and non-government education authorities have committed to providing in their curriculum at least two hours of physical activity each school week for primary and junior secondary school children under the Schools Assistance Act 2004. Also, the Australian Social Inclusion Agenda of the Australian Labor Party recommended that more young people from disadvantaged backgrounds complete twelve years of schooling and go on to further education and training. In Canada, due to the vast geographical dispersion of the population, many policies relating to health and education are conducted at the Provincial/Territorial level. Nova Scotia, for example, implemented the Annapolis Valley Health Promoting Schools programme in seven elementary schools, with preliminary results indicating that those schools which implemented the programme had sig ifi a tl lo e ates of o e eight a d o ese stude ts. The B itish Colu ia Child e s Hospital a d the U i e sit of B itish Colu ia i ple e ted a p og a e alled Health Buddies to e power elementary school children to live healthier lives by providing them with knowledge about health and physical activity. Results from the programme have shown that students had an increase in their healthyliving knowledge and BMI and less weight gain than students who were not in the programme. In Quebec the Take a e of ou health! p og a e deli e ed ACTI-MENU (a health promotion organization) aimed to provide employees with information and support risk factor reduction. Evaluation of the programme revealed that participants were more likely to report more frequent physical activity and better nutritional practices and absenteeism declined by 28% and turnover by 54%. As part of the National Health Promotion Act, Korea established national policies aimed at e ha i g people s health th ough health edu atio , disease p e e tio , ut itio i p o e e t a d the practice of healthy lifestyles. The Health Plan 2010 aims at improving the nutritional status of the population and a part of this was the revision and dissemination of dietary guidelines, enforcing mandatory nutrition labelling and providing information to groups deemed vulnerable such as the elderly and young children. Part of this strategy is to develop the plan in line with educational, political, economic and organizational means. The Health Plan 2010 includes activities focusing on the Social inequalities in health-related behaviours: Chapter 2 Is the grass greener on the other side? -72 -development of nutritious diets, development of obesity prevention and management programs and physical activity campaigns. 'Healthy Weight, Healthy Lives: A Cross-Government Strategy for England' targets children for healthy growth and healthy weight. Funded through the Department of Health, this strategy aims to reduce the proportion of overweight and obese children back to the levels found in 2000 by 2020. The NHS (National Health Service) has strategies aimed at offering public advice and support to those who already have weight problems through weight management programmes, NHS websites, as well as by developing the ability of health service staff to deal with issues of excess weight. Additionally, strategies exist in England to combat obesity through the promotion of healthier food choices, by limiting food advertising to children and working with the food industry to reduce salt, sugar and fat in foods; as well as st ategies su h as Walki g i to Health to uild ph si al a ti it i to the li es of the hole populatio a d A ti e E gla d ai ed at p o oti g o -sport physical activity.

Figure 1 .

 1 Figure 1. Trends in age-standardised obesity rates in Australia, Canada, England and Korea.

Figure 2 .

 2 Figure 2. Relationship between obesity and years of education Panel A: Men Panel B: Women

Figure 3 .

 3 Figure 3. Relationship between BMI and years of education Panel A: Men Panel B: Women

  Is the grass greener on the other side?

Figure 4 .

 4 Figure 4. Relationship between obesity and years of education by ethnicity groups in England Panel A : White Panel B : Black Panel C : Asian

Figure 5 .

 5 Figure 5. Relationship between obesity and years of education by minority status in Canada Panel A : Minority status: White Panel B : Minority status: Others

Figure 6 .

 6 Figure 6. Relationship between obesity and years of education by migrant groups in Australia Panel A : Migrant Panel B : Non-migrant

Figure 7

 7 describes the hypothesised mediation effect. Individual education contributes to determining individual socio-economic status (a), which in turn has an influence on the likelihood of obesity (b). Such mediated effect adds to the direct Is the grass greener on the other side?

Figure 7 .

 7 Figure 7. Indirect effect of individual education through individual socio-economic status

Figure 9 .

 9 Figure 9. Distribution of years of education according to obesity status at age 20

  Is the grass greener on the other side? -84 -

Figure 10 .Figure 11 .

 1011 Figure 10. Negative cohort effect with/without controls for education level in England

Figure 2 .

 2 Figure 2. WCIs for hazardous drinking by education level, before and after correcting for self-report bias Men Women

  fo ith the s ale α a d shape β pa a ete s as follo s: and Each individual (abstainers excluded) is assigned a new upshifted alcohol consumption amount on the basis of his/her percentile position in the original distribution. Weighted percentile rank is calculated for each individual in the original distribution. If two or more individuals have the same amount of alcohol, Social inequalities in health-related behaviours: Chapter 3 Is the grass greener on the other side?

Figure A1 .

 A1 Figure A1. Cumulative distribution of alcohol grams per day

Figure 2 .

 2 Figure 2. Inequity index for the need-adjusted probability of a GP visit and a specialist visit, and its 95% confidence intervals

Figure 3 .

 3 Figure 3. Inequality index for the probability of a dental visit and its 95% confidence intervals

Figure 4

 4 Figure 4 presents income-related inequalities in breast and cervical cancer screening (Panel A and B).

  Is the grass greener on the other side?

Figure 4 .

 4 Figure 4. Inequality index for cancer screening and its 95% confidence intervals

  atio d al ool et l utilisatio des se i es de sa t , da s plusieu s pa s de l OCDE. Ce t a ail repose sur une approche microéconométrique et utilise un grand nombre de bases de données nationales. Les objectifs de cette thèse sont de:(1) comparer les inégalités sociales de comportements de santé entre des pays ayant des caractéristiques différentes, (2) apporter un éclairage à la compréhension des disparités sociales des o po te e ts de sa t , et e fi e a i e o e t l auto-déclaration peut affecter l aluatio des o po te e ts de sa t , et do affe te la esu e des i galit s. Mots-clés : Inégalité sociale ; Obésité ; Alcool ; Accès aux soins ; Biais de déclaration ; Comparaison internationale __________________________________________________________________________________ Social Inequalities in Health-Related Behaviours: Is the grass greener on the other side? Marion Devaux Summary: This thesis deals with social inequalities in health-related behaviours such as lifestyle risk factors for health (precisely, obesity and alcohol consumption) and the utilisation of health care services, in a number of OECD countries. This work relies on an applied micro-economics approach, using several national health survey data. This thesis aims to (a) compare social inequalities in health-related behaviours across countries with different settings; (b) shed light on the understanding of social disparities in health-related behaviours; and (c) examine how self-reporting may affect the rating of behavioural risk-factors, and therefore affect the measurement of social inequalities. Key words: Social inequalities; Obesity; Alcohol; Health care access; Reporting bias; International comparison

  se so t i t ess es à o p endre les inégalités de santé et à explorer leurs déterminants (projet Eurothine, projet ECuity, van Doorslaer et Koolman, 2004 ; Cutler et Llerassuivi de la déclaration politique de Rio en 2011 sur les déterminants sociaux de la santé, en fa eu de plus d effo ts pou la du tio des i galit s de sa t .Les inégalités de santé sont un enjeu important pour les gouvernements pour deux raisons : elles sont injustes et engendrent des coûts so iau . Tout d a o d, les i galit s de sa t so t i justes pa e

	Social inequalities in health-related behaviours:		Summary/Résumé
	Is the grass greener on the other side?
	U g a d o e d tudes Mu e , . Du a t les de i es a	es, eau oup d atte tio a t po t e au d te i a ts de la
	santé, ota	e t a e la Co	issio des D te i a ts "o iau de la "a t de l OM" i iti e e	. Le
	t a ail e pa ette Co	issio a a outi à la pu li atio d u appo t e	« Closing the gap in a
	generation »,
				x

u elles peu e t appa aît e d s l e fa e et ue ha ue i di idu a pas les es ha es de o e santé (Trannoy et al., . Les i galit s des ha es li es au i o sta es da s l enfance représentent 46% des inégalités sociales de santé

  Tout d a o d, le p og a e de e he he du g oupe de t a ail de l U io Européenne sur « Socioeconomic Inequalities in Health », suivi du projet Eurothine (Tackling Health Inequality in Europe) mené par Johan Mackenbach et Anton Kunst, ont o t l e iste e de fo tes i galit s de sa t da s l U io Eu op e e da s les a es , et d i po ta tes a iatio s de l a plitude de es i galités, sugg a t u u e du tio des i galit s de sa t est possi le. Dans la lignée de ces recherches, le projet Européen EURO-GBD-SE a récemment ide tifi les poi ts d e t e les plus i po ta ts pou les politiques visant à réduire les inégalités de santé. Deuxièmement, le projet ECuity dirigé par Eddy van Doorslaer, Adam Wagstaff et Andrew Jones,

	Social inequalities in health-related behaviours:	Summary/Résumé
	Is the grass greener on the other side?
	i iti au d ut des a	es	, a appo t d i po ta tes a a es	thodologi ues et a o t i u au
			xv

Recommandations pour la recherche et implications politiques

  France et en Suède pour les hommes et en Espagne et en Corée pour les femmes. De plus, ette tude o t e ue les i galit s so iales d o sit so t plus a u es hez les fe es ue hez les ho es. Cette diff e e de ge e da s les dispa it s so iales d o sit a u e g a de i po ta e puisque les femmes ayant un faible niveau d du atio et u fai le statut so io-économique ont plus de ha e d t e o ses et de do e aissa e et d le e des e fa ts o ses, pe p tua t alo s le e le vicieux des inégalités sociales. Ainsi, en termes de recommandations politiques, cette analyse est-elle en fa eu d u i lage des g oupes de populatio à is ue tels ue les fe es a a t u fai le i eau d du atio et u fai le statut so io-économique. En outre, le chapitre 2 présente une analyse de la relation entre éducation et obésité menée sur xx esu e l effet du iais d auto-déclaration sur les inégalités sociales en corrigeant la distribution de o so atio d al ool pa des do es ag g es su les e tes d al ool. Les sultats o t e t ue les dispa it s so iales a ie t selo le ge e. Les fe es les plus du u es o t plus de ha e d adopte u e Les sultats p se t s da s ette th se o t d i po ta tes i pli atio s politi ues et o duise t à formuler des recommandations pour la recherche. Deux principales recommandations pour la recherche

	Social inequalities in health-related behaviours: Social inequalities in health-related behaviours: Social inequalities in health-related behaviours: Social inequalities in health-related behaviours:	Summary/Résumé Summary/Résumé Summary/Résumé Summary/Résumé
	Is the grass greener on the other side? Is the grass greener on the other side? Is the grass greener on the other side? Is the grass greener on the other side?
	atio d al ool à is ue selo le i eau d du atio et le es les oi s du u es, alo s u u e elatio i e se est o se e es da s la plupa t des pa s tudi s. Les esti atio s de la o so consommation à risque ue les fe hez les ho atio d al ool as es su les do es d e u te et elles issues de do es ag g es de e te p sentent de grandes diff e es. L a al se le u e e eu d esti atio du g adie t so ial due au iais d auto-déclaration da s les e u tes de o so atio d al ool. Ap s o e tio du iais d auto-déclaration, on trouve de plus fortes inégalités sociales chez les femmes, et de plus faibles inégalités -parfois même avec une les g alistes o t pas u ôle de oo di ateu de soi s, où l off e de soi s est esse tielle e t p i e, et où l a a e de f ais lo s des isites di ales est o ligatoi e. E te es d i pli atio s politi ues, et a ti le o t e ue alg les o je tifs atio au d uit d a s au soi s, des i i uit s selo le i eau de e enus persistent. Les résultats peu e t t e ti es de e t a ail. Tout d a o d, ette th se et e ide e de o euses li itatio s vis-à-is de l ha o isatio des do es et de la dispo i ilit des do es. Des a lio atio s se aie t nécessaires sur deux plans : a ha o ise les uestio s d e u tes da s le ut de fa ilite les plus larges en Le hapit e s i t esse à la o so comparaisons internationales, et (b) rendre les données disponibles aux chercheurs dans les délais plus
	groupe socio-économique. Ce papier, co-écrit avec Franco Sassi, a été soumis au journal European Journal sugg e t des pistes possi les ua t au fo es i stitutio elles pou a t fa o ise l uit d a s au
	xix

santé. Elle repose sur une approche micro-o o t i ue et utilise u g a d o e d e u tes nationales. Elle se compose de quatre chapitres. Le premier chapitre présente les données et méthodes e plo es da s les diff e tes a al ses. Les deu i e et t oisi e hapit es s i t esse t au odes de ie l o sit et le su poids da s le hapit e et la o so atio d al ool da s le hapit e . Le uat i e hapit e e a i e les i galit s d utilisatio des se i es de sa t li es aux revenus. Enfin, la conclusion générale offre une discussion des principaux résultats, propose des recommandations pour la recherche et discute les implications politiques. Le chapitre 1 présente les données et méthodes utilisées dans cette thèse. Les données issues d e u tes de sa t o t t olle t es pou 3 pays de l OCDE. Les esu es de l o sit , du su poids et de la o so atio d al ool so t d ites et leu alidit e ise e uestio . La fle io est ota e t po t e su u possi le iais d auto-déclaration des comportements à risque dans les enquêtes de santé et l effet de e iais su la esu e des i galit s. Ce hapit e p se te aussi les thodes e plo es pou alue les i galit s telles ue les i di es a solus et elatifs d i galit et l i di e de o e t atio . Le chapitre 2 examine le gradient social d o sit et de su poids da s pa s de l OCDE. Ce travail, co-écrit avec Franco Sassi, a été publié dans le journal European Journal of Public Health en 2013. Les i galit s d o sit li es au i eau d du atio et au statut so io-économique sont mesu es à l aide des i di es a solus et elatifs d i galit . Les sultats o t e t ue les i di es a solus et elatifs d i galit aptu e t des di e sio s diff e tes et peu e t o dui e à des lasse e ts de pa s différents. Par exemple, pour les inégalit s li es au i eau d du atio , les i galit s a solues so t plus larges en Hongrie et en Espagne pour les hommes et les femmes, alors que les inégalités relatives sont cinq pays (Angleterre, Australie, Canada, Corée, et France). Cette étude co-écrite avec Franco Sassi, Jody Church, Michele Cecchini et Francesca Borgonovi, a été publiée dans le journal OECD Economics Journal en 2011. Une relation quasi linéaire est ise e ide e e t e le o e d a es d du atio et la p o a ilit d o sit . Ce sultat sugg e u u e a e suppl e tai e d du atio à uel ue i eau ue e soit o dui ait à dui e le is ue d o sit da s u e p opo tio si ilai e, si le lien de causalité de l du atio e s l o sit tait o fi . Cepe da t, le lie de ausalit e t e du atio et o sit a pas t d o t a e e titude. U e a al se su do es f a çaises o t e ue l asso iatio e t e du atio et o sit est ue fai le e t affe t e lo s u o tie t o pte des oppo tu it s duites d du atio pou les i di idus o ses au âges jeu es. Ce sultat sugg e ai si ue la ausalit prédomine dans le sens éducation vers obésité. De plus, l a al se des effets de diatio via la position socio-o o i ue de l i di idu et l a al se des effets de o u e e ia le i eau d du atio de la mère montrent ue l du atio affe te l o sit esse tielle e t de a i e di e te. E fi , les sultats mettent en évidence non seulement un effet absolu de l du atio su l o sit , mais aussi un effet relatif, est-à-dire que le i eau d du atio de l i di idu relativement à celui de ses pairs a une i flue e su l o sit . En termes de recommandations politiques, cet article encourage davantage d i estisse e t da s l du atio pou aide à dui e l o sit , via des programmes favorisant l allo ge e t de la s ola isatio et des p og a es d du atio à la sa t , ota e t e di e tio des individus défavorisés et quittant prématurément le système scolaire. of Public Health e . L a al se ou e pa s de l OCDE, et e a i e les dispa it s so iales elati es à la consommation à risque telle que déclarée dans les enquêtes de santé. De plus, ce papier cherche à inversion du gradient social-chez les hommes. Ainsi cet article est-il non seulement en faveur de politiques ciblées vers les groupes de population les plus à risque, mais il appelle aussi à davantage d effo ts su les thodologies d e u te pou a lio e la esu e et le o t ôle de la o so atio à risque au niveau individuel. Le hapit e t aite des i i uit s d utilisatio des se i es de sa t da s pa s de l OCDE, et te te d e a i e le ôle des a a t isti ues i stitutio elles atio ales e ta t ue d te i a ts pote tiels de ces iniquités. Cet article a été publié dans le journal European Journal of Health Economics en 2013. Les services de santé examinés sont les suivants : les visites chez le médecin (généraliste et spécialiste), les isites hez le de tiste, et le d pistage de a e . Le deg des i galit s est esu à l aide d u indice de concentration corrigé pour tenir compte des variations de la prévalence de la variable de santé étudiée entre pays. Les résultats montrent des iniquités en faveur des plus riches pour les visites chez un médecin (iniquité fortement marquée pour les visites de spécialistes), ainsi que pour les visites de dentiste et de dépistage de ca e . Bie ue l a al se des o latio s a e les a a t isti ues i stitutio elles atio ales ait t li it e pa les do es, et e a e a pe is d appo te u lai age intéressant. On observe notamment que les pays qui présentent de plus larges iniquit s so t eu a a t pas de couverture universelle de santé, ceux où le financement de la santé repose largement sur l assu a e p i e et les paie e ts di e ts des usage s, où soi s, et sugg e t u u o t ôle o ti u des i i uit s d utilisatio des se i es de sa t est esse tiel pour évaluer le succès des politiques futures. xxi 5. courts. Ensuite, au-delà de la mesure et du contrôle des inégalités de santé, il semble nécessaire de po te plus d effo ts à la o p he sio de es i galit s pou aide à la d fi itio de politi ues plus effi a es pou dui e es i galit s e . ide tifie l i pa t ausal des d te i a ts des i galit s . En ce qui concerne les implications pour les politiques publiques, les résultats de cette thèse ette t e ide e des le ie s d a tio possi les pou aide à lutte o t e les i galit s so iales de comportements de santé, et plus généralement réduire les i galit s so iales de sa t . Tout d a o d, cette thèse suggère que pour des mesures politiques efficaces, il est important de cibler les groupes de populatio les plus à is ue, e pa ti ulie les i di idus a a t u plus fai le i eau d du atio et u faible statut socio-économique qui concentrent une plus forte prévalence de facteurs de risque, et les individus à bas revenus ui o t da a tage de a i es d a s au soi s. Des politi ues de edist i utio mieux ciblées (ex. transferts monétaires, filets de protection sociale) combinées à des politiques de santé isa t les plus d fa o is s e . p og a es i l s d du atio à la sa t et de p e tio peu e t aide à réduire les inégalités de comportements de santé. Deuxièmement, comme exposé dans cette thèse, la santé et les inégalités de santé sont liées à de o euses aut es di e sio s telles ue l du atio , l e ploi et le e e u. D u poi t de ue politi ue, il apparaît donc intéressant de prendre en considération ces relations multisectorielles et de concevoir la politi ue de sa t au e t e d u age da politi ue plus la ge. O peut pe se pa e e ple à i lu e des objectifs de santé dans les autres secteurs politiques (ex. éducation, emploi et affaires sociales). Par exemple, au Japon, un programme de prévention des maladies chroniques est actuellement mis en place sur le lieu de travail dans le but de maintenir les employés plus longtemps en activité et en bonne santé, afi d a lio e la p odu ti it au t a ail. Bie e te du, de telles i itiatives impliquent de mettre en

  Tout d a o d, l a al se de la elatio e t e du atio et o sit off e u lai age su la atu e du lie et te te d alue le se s de la ausalit . Cepe da t, l i estigatio du lie ausal est li it e du fait des données transversales dont nous disposions à ce moment-là, alors que des données longitudinales auraient été plus appropriées. Afin de mener des explorations plus poussées, il serait intéressant xxiv aux soins bien que les effets varient entre pays européens (Eurofound, 2013). De même les dernières do es eu op e es de l e u te EU-SILC 2012 indiquent une augmentation du non-recours aux services de santé suite à la crise parmi les plus défavorisés (OCDE, 2014). Dans les mois à venir, alors que de nouvelles do es se o t ises à dispositio des he heu s, il se ait i t essa t d alue l i pa t de la ise su l utilisatio des se i es de sa t et su la sa t elle-même selon le statut socio-économique. Impacts of the crisis on access to healthcare services in the EU, Dublin. Eurostat (2010), Highly educated men and women likely to live longer . Available at: http://epp.eurostat.ec.europa.eu/cache/ITY_OFFPUB/KS-SF-10-024/EN/KS-SF-10-024-EN.PDF Eurothine project, website available at http://www.euro-gbd-se.eu/ Tubeuf S, Trannoy A. (2013 , Les diff e es d tat de sa t e F a e: i galit s des ha es ou eflet des o po te e ts à is ues? Économie et Statistique, 455-456. Health at a Glance Europe, Paris. O ), Jusot F, Yil az E. . I pa t of Health a e " ste o "o ioe onomic Inequalities in Doctor Use . IRDES Working Paper No.17. IRDES, Paris. Kippe sluis H, a d Gala a T. , Wh the 'i h d i k Mo e ut s oke Less: The I pa t of Wealth o Health Beha io s . Tinbergen Institute Discussion Paper TI 2013-035/V.

	Social inequalities in health-related behaviours: Social inequalities in health-related behaviours: Social inequalities in health-related behaviours: Social inequalities in health-related behaviours: Social inequalities in health-related behaviours:	Summary/Résumé Summary/Résumé Summary/Résumé Summary/Résumé Summary/Résumé
	Is the grass greener on the other side? Is the grass greener on the other side? Is the grass greener on the other side? Is the grass greener on the other side? Is the grass greener on the other side?
	Cutler D, Lleras-Muney A. of Health Economics, 29: 1-28. , Understanding differences in health behaviors by education . Journal ECuity project, website available at: http://www2.eur.nl/bmg/ecuity/ Ljungvall Å, Gerdtham U-G, Li d lad U. , Mis epo ti g a d is lassifi atio : i pli atio s fo socioeconomic disparities in body-ass i de a d o esit . Lu d U i e sit Wo ki g pape . http://project.nek.lu.se/publications/workpap/papers/WP12_19.pdf Llena-Nozal A. health and well-ei g , European Journal of Health Economics, 12(5):429-444. Sassi F, Cecchini M, Lauer J, and Chisholm D. (2009), Improving Lifestyles, Tackling Obesity: The Health and Economic Impact of Prevention Strategies . OECD Health Working Paper 48. Eurofound (2013), Health Economics, Elsevier: 348-408. Jusot F, Lakda alla D, a d Philipso T. , The G o th of O esit a d Te h ologi al Cha ge: A Theo eti al a d E pi i al E a i atio . Wo ki g Pape , http://www.nber.org/papers/w8946 , Co t a tual o ditio s, o ki g o ditio s a d thei i pa t o a Woodward A, and Kawachi I. , Wh edu e health i e ualities? J Epidemiol Community Health, OECD (2014), 'o o e ", Jo es A a d 'i e N. 54:12 923-929.
	Jusot F (2010) Les interventions de réduction des inégalités sociales de santé en Europe in Réduire les van Doorslaer E, Wagstaff A, Bleichrodt H, Calonge S, Gerdtham U, Gerfin M, Geurts J, Gross L, Häkkinen
	Quat i e e t, alo s ue l tude su l utilisatio des se i es de sa t inégalités sociales en santé, L. Potvin, M-J Moquet et C. M. Jones (sous la dir.), Inpes, pp.73-88. et e ide e des Alcohol and Alcoholism, 48(2): 241-249. U, Leu R, O'Donnell O, Propper C, Puffer F, Rodriguez M, Sundberg G and Winkelhake O. (1997),
	i i uit s pe sista tes, il se ait i t essa t d e a i e l effet de la ise o o i ue de l utilisatio des se i es de sa t et d alue da s uelle esu e la ise au ait o t i u à a oît e les su "o ioe o o i i e ualities i health: so e i te atio al o pa iso s , Journal of Health Morris S. (2007), The I pa t of O esit o E plo e t , Labour Economics, 14:413-433. Jusot F, a d Khlat M. Economics, 16(1): 93-112.
	xxvi xxvii xxviii xxix

d a al se le lie ausal su do es lo gitudi ales o e pa e e ple elles du British Household Panel Survey ou de l e u te Household, Income and Labour Dynamics in Australia. Deu i e e t, l tude su les i galit s de o so atio à is ue d alcool met en évidence d i po ta tes li itatio s su les do es d e u te ua t à la esu e de la o so atio d al ool. La o so atio d al ool appa aît la ge e t sous-esti e da s les do es d e u te. Alo s ue les do es d e u te o t t o ig es du iais d auto-déclaration en utilisant des données agrégées de e te d al ool, u e ou elle te h i ue de o e tio a t e e t a a e utilisa t deu t pes de uestio s da s les e u tes, l u e su la ua tit -f ue e de o so atio et l aut e sur la o so atio la eille de l e u te Meie et al., 2013; Stockwell et al., 2014). De nouvelles analyses utilisa t ette thode de o e tio pou ait he he à o fi e l e iste e d u e e eu d esti atio des inégalités de consommation à risque d al ool due au iais d auto-déclaration dans les enquêtes. T oisi e e t, l tude su l utilisatio des se i es de sa t he he t à appo te u lai age su le ôle des a a t isti ues i stitutio elles atio ales. N a oi s, l a al se est fo te e t limitée par le faible nombre de pays étudiés, et donc, par le manque de variabilité au niveau pays. De nouvelles a al ses plus o ustes utilisa t des od les ulti i eau pou aie t t e e es à o ditio d a de à des bases de données adéquates per etta t d a oît e le o e des pa s tudi s. i galit s so iales d a s au soi s. U e tude e te o t e ue la ise a o duit à d t io e l a s Filippidis FT, Schoretsaniti S, Dimitrakaki C, Vardavas CI, Behrakis P, Connolly GN, Tountas Y. (2014), T e ds i a dio as ula isk fa to s i G ee e efo e a d du i g the fi a ial isis: the i pa t of social dispa ities . European Journal of Public Health. doi: 10.1093/eurpub/cku028 Fu hs V'. , Ti e p efe e e a d health: A e plo ato stud . I V' Fu hs eds , E o o i aspects of health. Chicago: University of Chicago Press. 93-120. Galama T and Va Kippe sluis H. , Health Inequalities through the Lens of Health Capital Theory: Issues, "olutio s, a d Futu e Di e tio s . Tinbergen Institute Working paper No. 13-076/V. Gordon-Larsen P, Nelson MC, Page P, Popkin BM. , I e ualit i the Built E i o e t U de lies Ke Health Dispa ities i Ph si al A ti it a d O esit . Pediatrics, 117(2):417-424. G oss a M. , O the o ept of health apital a d the de a d fo health . The Journal of Political Economy, 80(2), 223-255. G oss a M. . The Hu a Capital Model , i Cul e A.J., Ne house J.P. eds , Handbooks of , The ole of ti e a d isk p efe e es i s oki g i e ualities: A populatioased stud . Addictive Behaviors, 38:2167-2173. , The effe t of o k status a d o ki g o ditio s o e tal health i fou OECD ou t ies , National Institute Economic Review, 209(1):72-87. Lundborg P, Nystedt P and 'ooth D. , No Cou t fo Fat Me ? O esit , Ea i gs, "kills, a d Health a o g , " edish Me . IZA Discussion Paper No. 4775, www.ed.lu.se/papers/iza_lundborg.pdf. Ma ke a h JP, Mee di g WJ, Ku st AE, , E o o i osts of health i e ualities in the European U io . J Epidemiol Community Health, 65:412-419. Ma ke a h JP, "ti u I, 'oska A', " haap MM, Me ielle G, Lei salu M et al. , "o ioe o o i I e ualities i Health i Eu opea Cou t ies . The New England Journal of Medicine, 358: 2468-2481. M Gi is J, Foege WH. , A tual auses of death i the U ited "tates . Journal of the American Medical Association, 270, 2207-2212. Meier PS, Meng Y, Holmes J, Baumberg B, Purshouse R, Hill-M Ma us D, et al., , Adjusti g for unrecorded consumption in survey and per capita sales data: Quantification of impact on genderand age-specific alcohol-att i uta le f a tio s fo o al a d pha geal a e s i G eat B itai . OECD , Ho s Life? Measu i g Well-Being. OECD, Paris; 2011. Stockwell T, Zhao J, and Macdonald S. , Who u de -reports their alcohol consumption in telepho e su e s a d ho u h? A appli atio of the este da ethod i a atio al Ca adia su sta e use su e . Addiction, doi:10.1111/add.12609. Stringhini S, Sabia S, Shipley M, Brunner E, Nabi H, Kivimaki M, Singh-Manoux A. (2010 , Association of socioeconomic position with health behaviors and mortality. The Whitehall II study . JAMA, 303(12): 1159-1166. T a o A, Tu euf ", Jusot F a d De au M, , I e ualit of Oppo tu ities i Health i F a e : a fi st pass . Health Economics, 19(8):921-38. Van der Pol M. (2011), Health, Edu atio a d Ti e P efe e e . Health Economics, 20:917-929. van Doorslaer E, a d Kool a X. , E plai i g the diffe e es i i o e-related health inequalities a oss Eu opea ou t ies , Health Economics, 13: 609-628. a Doo slae E, a d Masse ia C. . I o e-related Inequality in the Use of Medical Care in 21 OECD Cou t ies . OECD Health Working Paper No.14. OECD, Paris.

4.1. Research questions

	General Introduction
	Is the grass greener on the other side?
	Under the broad objective of examining social inequalities in health-related behaviours in different
	countries, this thesis addresses important research questions regarding the methodology and related

Table 1 .

 1 List of national health surveys used

	Country	Survey name	Data provider
	Australia	National Health Survey 2007-08	Australian Bureau of Statistics
	Austria	Österreichische Gesundheitsbefragung 2006/07 (EHIS)	Eurostat for the EHIS version
	Belgium	Belgium Health Survey 2008 (EHIS)	Operational Direction Public Health and Surveillance of the Scientific Institute of Public Health (WIV-ISP)
	Canada	National Health Population Survey and Canadian Community Health Survey 2009/10	Statistic Canada
	Czech Republic	European Health Interview Survey in the Czech Republic 2008 (EHIS)	Institute of Health Information and Statistics (UZIS)
	Estonia	Estonian Health Interview Survey 2006/07 (EHIS)	Eurostat for the EHIS version
	Finland	Finrisk 2007 /

Welfare and services Survey (HYPA -survey) 2009 National Institute for Health and Welfare (THL) France Enquête Santé et Protection Sociale 2008-10 Institute for Reseach and Information in Health Economics (IRDES) Germany Epidemiological Survey on Substance Abuse 2009 / German Telephone Health Interview Survey (GEDA) 2009 ESA: GESIS -Leibniz Institute for the Social GEDA: Robert Koch Institute Hungary European Health Interview Survey (EHIS) 2009 Hungarian Central Statistical Office Ireland Survey on Lifestyle And Nutrition 2007 Irish Social Science Data Archive Italy Condizioni di Salute 2005 / Multiscopo Aspect of Daily Life 2010 Italian National Institute of Statistic Japan National Survey on Alcohol Drinking and Lifestyle 2008 Tottori University Korea Korean National Health and Nutrition Examination Survey 2008 Jointly carried out by the Korean Institute for Health and Social Affairs and the Korean Health Industry Develpment Institute New Zealand National Health Survey 2006/07 Ministry of Health Poland Europejskie Ankietowe Badanie Zdrowia 2009 (EHIS) Eurostat for the EHIS version Slovak Republic Európsky prieskum zdravia 2009 (EHIS) National Health Information Centre (Ministry of Health) Slovenia Anketa o zdravju in zdravstvenem varstvu 2007 (EHIS) Institute of Public Health Spain Encuesta Nacional de Salud de Espana 2006 / Encuesta Europea de Salud 2009 Instituto Nacional de Estadistica and Ministry of Public Health, Social Services and Equality BHPS: Institute for Social and Economic Research HSE: Office for Population Censuses and Surveys (1991-1993), then (since 1994) conducted by the Joint Survey Unit of the National Centre for Social Research (NatCen) and the Department of Epidemiology and Public Health at University

of good health Relative position on the socioeconomic scale

	20% 40% 60% Rate Social inequalities in health-related behaviours: Is the grass greener on the other side?					Chapter 1
	0%
	0	0.2	0.4	0.6	0.8	1
	It is worth noting that the relative and absolute indices of inequality are two complementary
	measures with different properties. The RII is invariant to equiproportionate change, i.e. if everyo e's

of good health Cumulative % of population ranked by wealth

  For instance, if the immunization rate doubles.

	Social inequalities in health-related behaviours:					Chapter 1
	Is the grass greener on the other side?
	100%
	80%
	60%
	20% 40% Cumullative % Equality line	Concentration curve
	0%
	0%	20%	40%	60%	80%	100%

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E e ge s G.

, Co e ti g the Co e t atio I de . Journal of Health Economics,28:504-515. Fu t ae gle N, a d de Visse '. , La k of o se sus i lo -risk drinki g guideli es . Drug and Alcohol Review; 32:11-18. Hernández-Quevedo C, Jo es AM, 'i e N. , 'epo ti g Bias a d Hete oge eit i "elf-Assessed Health: E ide e f o the B itish Household Pa el "u e . Yo k: U i e sit of Yo k. Jü ges H. , T ue Health s 'espo se "t les: E plo i g C oss-Country Differences in Self-Reported Health . Health Economics, 16:163-178. Mackenbach JP, Stirbu I, Roskam AR, Schaap MM, Menvielle G, Leinsalu M, et al. , "o ioe o o i I e ualities i Health i Eu opea Cou t ies . The New England Journal of Medicine, 358:2468-2481. , 'epo ti g Hete oge eit i "elf-Assessed Health Among Elderly Eu opea s . Health Economics Review, 2(1):21. Rehm J, Kehoe T, Gmel G, et al. , "tatisti al odeli g of olu e of alcohol exposure for epide iologi al studies of populatio health: the U" e a ple . Population Health Metrics, 8:3. Sassi F, Devaux M, Cecchini M and Rusticelli E. (2009), The O esit Epide i : A al sis of Past a d P oje ted Futu e T e ds i "ele ted OECD Cou t ies . OECD Health Working Papers No. 45, OECD Publishing. "e gea t J a d Fi th D. , 'elati e i de of i e ault : defi itio , esti atio , a d i fe e e . a o pa iso of uestio ai e a d dia easu es , Alcohol and Alcoholism, 37(2);187-92. WHO (2014), Global status report on alcohol and health. World Health Organization 2014. Switzerland. )hao J, "to k ell T, Ma do ald ". , No -espo se ias i al ohol a d d ug populatio su e s .

  explored health inequalities in 22 European countries in relation

	Social inequalities in health-related behaviours:	Chapter 2
	Is the grass greener on the other side?

Chapter 2

 2 Is the grass greener on the other side?

	-55 -

ANNEXES Supplementary File No.1-Table: Description of the data

  Note: Overweight rates include obesity. Rates were age-standardised using the 2005 OECD standard population.

					Men	Wom en	Men	Wom en
	Australia	National Health surveys	1995, 2001 and 2005	80,215	18.00%	16.00%	59.50%	42.10%
		Mikrozensus +
	Austria	Health Interview	1999 and 2007	42,059	10.90%	10.70%	50.80%	34.00%
		Survey
		National Health
	Canada	Population Survey +Canadian Community Health	1994-95, 2000-01, 2003, 2005	266,782	17.20%	15.80%	54.20%	39.60%
		Survey
	England	Health Survey for England	Annually from 1995 to 2007	114,807	21.60%	22.50%	60.70%	52.20%
	France	Enquête Santé et Protection Sociale

  IntroductionOverweight and obesity rates have been increasing sharply over recent decades in all industrialised countries, as well as in many lower income countries. The rise in obesity has reached epidemic

	Social inequalities in health-related behaviours:						Chapter 2
	Is the grass greener on the other side?
				Figure A13: Trends in the US, in other ethnic population group
				Panel A. Men				Panel B. Women
		90% 90%						90% 90%
	Rates of obesity and overweight Rates of obesity and overweight	0% 10% 20% 30% 40% 50% 60% 70% 80% 80% 0% 10% 20% 30% 40% 50% 60% 70%	Overweight Obesity Overweight Obesity				Rates of obesity and overweight Rates of obesity and overweight	0% 10% 20% 30% 40% 50% 60% 70% 80% 80% 0% 10% 20% 30% 40% 50% 60% 70%	Overweight Obesity Overweight Obesity
		1998 1998	2000 2000	2002 2002	2004 2004	2006 2006	2008 2008	1998 1998	2000 2000	2002 2002	2004 2004	2006 2006	2008
				Year Year						Year Year
			Lower education Lower education	Middle education Middle education	Higher education Higher education		Lower education Lower education	Middle education Middle education	Higher education Higher education
	0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Exploring the Relationship between Education Rates of obesity and overweight 90% Overweight Overweight Obesity 0% 10% 20% 30% 40% 50% 60% 70% 80% Obesity Rates of obesity and overweight and Obesity
		1998	2000	2002	2004	2006	2008	1998	2000	2002	2004	2006
	Year Middle education Marion Devaux, Franco Sassi, Jody Church, Michele Cecchini, Francesca Borgonovi Lower education Higher education Year Lower education Middle education Higher education
	OECD Economics Journal, 2011
		100%						90%
	Rates of obesity and overweight	0% 10% 20% 30% 40% 50% 60% 70% 80% 90%	Overweight Obesity				Rates of obesity and overweight	80% 0% 10% 20% 30% 40% 50% 60% 70%	Overweight Obesity
		1998	2000	2002	2004	2006	2008	1998	2000	2002	2004	2006
				Year						Year
			Lower education	Middle education	Higher education		Lower education	Middle education	Higher education
							-61 -

Table 1 .

 1 Odds ratios and significance for the probability of obesity in England

	Note: (***) means significant at 1%, (**) at 5%, (*) at 10%.

Source: Cross-sectional survey data from Health Survey for England 1991-2005; Autho s al ulatio s.

Table 2 .

 2 Odds ratios and significance for the probability of obesity in Korea Autho s al ulatio s.

	Note: (***) means significant at 1%, (**) at 5%, (*) at 10%.
	Source: Cross-sectional survey data from KNHANES 1998-2005;

Table 3 .

 3 Odds ratios for obesity in adulthood in France (age range

	Note: (***) means significant at 1%, (**) at 5%, (*) at 10%.
	Source: French data from Enquête Décennale Santé 2002-03; Autho s al ulatio s.

  as follows.

	Social inequalities in health-related behaviours:		Chapter 2
	Is the grass greener on the other side?
		Model 1: without control	Model 2: with control for
	France	for obesity at age 20	obesity at age 20
	Odds Ratios Significance Odds Ratios Significance
	Age	1.13 ***	1.14 ***
	Age squared	1.00 ***	1.00 ***
	Women	1.26 **	1.31 **
	Years of education -Men
	0-5 years	ref.	ref.
	6-8 years	0.93	0.98
	9-11 years	0.75 **	0.79
	over 12 years	0.85 *	0.90
	Years of education -Women
	0-5 years	ref.	ref.
	6-8 years	0.84 *	0.83 *
	9-11 years	0.54 ***	0.54 ***
	over 12 years	0.52 ***	0.53 ***
	Obese at age 20		15.53 ***
	Occupation (SES)
	Blue collar workers	ref.	ref.
	Craftmen	0.82 **	0.81 **
	Farmers	0.88	0.84
	Clerks	0.82 ***	0.82 ***
	Intermediate professions	0.65 ***	0.66 ***
	Managers, Professionals	0.42 ***	0.43 ***
	Working status
	Working	ref.	ref.
	Not working	1.29 ***	1.29 ***

Table 4 .

 4 Odds ratios and significance for likelihood of obesity when controlling for cohort education level Note: In Australia and Canada age squared is not available as the age variable is categorical; we use mid-

		Australia	Canada	England	Korea
	Age	1.060 ***	1.026 ***	1.157 ***	0.992
	Age squared			0.999 ***	1.000
	Women	0.859 ***	0.808 ***	1.138 ***	1.179
	Individual education	0.912 ***	0.959 ***	0.913 ***	0.921 ***
	Educational environment	3.347 ***	1.184 ***	2.015 ***	0.989
	SES
	highest	ref.	ref.	ref.	ref.
	middle-high	1.179 ***	1.099 ***	1.232 ***	0.946
	middle	1.158 ***	1.104 ***	1.221 ***	0.912
	middle-low	1.531 ***	1.106 **	1.397 ***	1.057
	lowest	1.365 ***	1.189 ***	1.488 ***	1.200
	Ethnicity
	White			ref.
	Black			1.675 ***
	Asian			0.780 ***

age of each category. (***) means significant at 1%, (**) at 5%, (*) at 10%. Source: Autho s calculations based on national survey data.

Table A .1.1

 A Australia -National Health Survey

	Social inequalities in health-related behaviours:								Chapter 2
	Is the grass greener on the other side?
			Australia	men	women 1989	total	men	women 1995	total	men	women 2001	total	men	women 2005	total
		Total frequency	12,499	12,490	24,989	10,932	10,904	21,836	4,744	5,164	9,908	5,348	5,590	10,938
			25-39	16.5%	16.7%	16.6%	15.3%	15.6%	15.4%	11.4%	12.8%	12.1%	12.4%	12.9%	12.7%
			30-34	16.2%	16.5%	16.4%	15.9%	16.1%	16.0%	13.9%	15.1%	14.4%	14.4%	15.0%	14.7%
	Age group	35-39 40-44 45-49	15.1% 14.6% 11.7%	15.4% 14.5% 11.1%	15.2% 14.5% 11.4%	15.2% 14.0% 12.9%	15.6% 14.0% 13.1%	15.4% 14.0% 13.0%	14.9% 15.2% 13.3%	15.4% 14.3% 13.2%	15.1% 14.8% 13.2%	13.9% 14.4% 13.2%	14.4% 14.6% 13.2%	14.1% 14.5% 13.2%
			50-54	9.4%	9.2%	9.3%	10.7%	10.1%	10.4%	13.1%	12.1%	12.6%	11.6%	11.3%	11.5%
			55-59	8.3%	8.2%	8.2%	8.7%	8.0%	8.4%	10.1%	9.3%	9.7%	11.3%	10.3%	10.8%
			60-64	8.2%	8.5%	8.3%	7.4%	7.4%	7.4%	8.2%	7.8%	8.0%	8.8%	8.2%	8.5%
	Equivalized income	upper upper middle middle lower middle lower	31.6% 25.6% 20.0% 13.9% 8.9%	26.9% 23.6% 19.5% 17.4% 12.6%	29.3% 24.6% 19.8% 15.6% 10.7%	30.0% 23.6% 18.8% 12.7% 15.0%	26.0% 22.3% 18.5% 16.5% 16.6%	28.0% 23.0% 18.7% 14.6% 15.8%	31.3% 22.5% 19.4% 12.9% 13.9%	25.7% 21.9% 19.2% 16.0% 17.1%	28.6% 22.2% 19.3% 14.4% 15.5%	30.4% 24.4% 19.8% 14.5% 10.9%	24.4% 21.0% 21.1% 17.1% 16.4%	27.5% 22.8% 20.4% 15.8% 13.6%
	Migrant	yes no	31.2% 68.8%	29.2% 70.8%	30.2% 69.8%	29.8% 70.2%	29.2% 70.8%	29.5% 70.5%	29.2% 70.8%	28.9% 71.1%	29.1% 70.9%	28.4% 71.6%	28.9% 71.1%	28.7% 71.3%
	Obese	no yes	90.8% 9.2%	89.6% 10.4%	90.2% 9.8%	86.4% 13.6%	86.5% 13.5%	86.4% 13.6%	82.8% 17.2%	81.8% 18.2%	82.3% 17.7%	78.1% 21.9%	81.6% 18.4%	79.8% 20.2%
	Over-	weight	no yes	51.3% 48.7%	67.0% 33.0%	59.0% 41.0%	43.8% 56.2%	60.7% 39.3%	52.0% 48.0%	37.9% 62.1%	55.7% 44.3%	46.6% 53.4%	32.2% 67.8%	53.0% 47.0%	42.3% 57.7%
	BMI	classification	underweight normal overweight obese	1.1% 50.1% 39.5% 9.2%	5.1% 61.9% 22.6% 10.4%	3.1% 55.9% 31.2% 9.8%	0.9% 42.9% 42.6% 13.6%	3.7% 57.0% 25.7% 13.5%	2.3% 49.8% 34.4% 13.6%	0.8% 37.2% 44.8% 17.2%	3.4% 52.2% 26.2% 18.2%	2.1% 44.5% 35.7% 17.7%	0.5% 31.7% 45.9% 21.9%	3.0% 50.0% 28.6% 18.4%	1.7% 40.6% 37.5% 20.2%
	Years of	education	0-8 9-11 over 12	17.8% 65.8% 16.4%	17.9% 70.2% 11.9%	17.9% 68.0% 14.2%	13.8% 67.1% 19.2%	13.2% 71.2% 15.6%	13.5% 69.1% 17.4%	10.0% 67.6% 22.4%	8.3% 72.1% 19.6%	9.2% 69.8% 21.0%	6.7% 45.6% 47.7%	5.4% 44.0% 50.6%	6.1% 44.8% 49.1%
								-99 -

Table A .1.2

 A Canada -Canadian National Population Health Survey 1995 and Canadian Community Health Survey 2001-2005

			Canada	men	women 1995	total	men	women 2001	total	men	women 2003	total	men	women 2005	total
		Total frequency	5,009	5,560	10,569	35,044	36,852	71,896	33,154	34,911	68,065	33,471	35,495	68,966
			25-39	13.9%	12.6%	13.2%	12.0%	11.5%	11.8%	12.0%	11.4%	11.7%	11.8%	11.6%	11.7%
			30-34	16.3%	17.5%	16.9%	13.3%	12.5%	12.9%	11.9%	12.0%	12.0%	11.7%	11.8%	11.7%
	Age group	35-39 40-44 45-49	17.1% 14.8% 13.2%	16.4% 14.7% 12.0%	16.8% 14.7% 12.6%	15.6% 16.5% 14.0%	15.9% 16.5% 14.7%	15.7% 16.5% 14.4%	15.0% 16.6% 13.6%	14.8% 16.4% 14.2%	14.9% 16.5% 13.9%	13.3% 16.4% 14.3%	13.1% 16.0% 14.9%	13.2% 16.2% 14.6%
			50-54	10.2%	9.9%	10.0%	12.2%	12.4%	12.3%	12.4%	12.8%	12.6%	12.5%	13.3%	12.9%
			55-59	7.7%	8.8%	8.2%	9.4%	9.2%	9.3%	10.6%	10.6%	10.6%	11.2%	10.9%	11.1%
			60-64	7.0%	8.1%	7.5%	7.0%	7.4%	7.2%	7.8%	7.8%	7.8%	8.8%	8.4%	8.6%
	Equivalized income	upper upper middle middle lower middle lower	19.9% 41.1% 25.6% 8.8% 4.7%	16.5% 37.9% 28.3% 11.4% 5.9%	18.2% 39.5% 26.9% 10.1% 5.3%	37.7% 37.1% 17.1% 4.8% 3.3%	31.8% 36.6% 20.2% 7.3% 4.1%	34.8% 36.8% 18.6% 6.0% 3.7%	45.0% 34.2% 14.6% 3.8% 2.4%	37.7% 35.9% 17.7% 5.6% 3.0%	41.5% 35.0% 16.1% 4.7% 2.7%	54.2% 26.0% 12.9% 3.0% 3.9%	47.6% 27.1% 15.9% 4.1% 5.3%	51.0% 26.6% 14.4% 3.5% 4.5%
	Minority	no yes				86.0% 14.0%	85.9% 14.1%	86.0% 14.0%	84.3% 15.7%	85.3% 14.7%	84.8% 15.2%	83.6% 16.4%	84.0% 16.0%	83.8% 16.2%
	Obese	no yes	85.9% 14.1%	86.1% 13.9%	86.0% 14.0%	82.5% 17.5%	84.8% 15.2%	83.6% 16.4%	82.1% 17.9%	84.2% 15.8%	83.1% 16.9%	81.2% 18.8%	83.8% 16.2%	82.5% 17.5%
	Over-	weight	no yes	39.0% 61.0%	59.2% 40.8%	49.0% 51.0%	40.4% 59.6%	57.4% 42.6%	48.7% 51.3%	38.5% 61.5%	57.0% 43.0%	47.5% 52.5%	37.7% 62.3%	56.4% 43.6%	46.7% 53.3%
	BMI	classification	underweight normal overweight	0.5% 38.5% 46.9%	2.6% 56.6% 27.0%	1.5% 47.4% 37.1%	0.9% 39.5% 42.1%	3.4% 53.9% 27.5%	2.1% 46.6% 34.9%	0.7% 37.8% 43.6%	3.1% 54.0% 27.1%	1.9% 45.6% 35.6%	0.7% 37.1% 43.5%	3.5% 52.9% 27.5%	2.0% 44.7% 35.7%
			obese	14.1%	13.9%	14.0%	17.5%	15.2%	16.4%	17.9%	15.8%	16.9%	18.8%	16.2%	17.5%
	Years of	education	8 12 14	21.6% 14.9% 23.7%	21.1% 18.4% 25.0%	21.4% 16.6% 24.3%	18.1% 18.2% 6.9%	16.8% 21.3% 7.3%	17.4% 19.7% 7.1%	14.1% 18.0% 6.3%	13.3% 19.6% 6.6%	13.7% 18.7% 6.5%	12.4% 14.8% 7.1%	10.7% 15.8% 6.7%	11.6% 15.3% 6.9%
			17	39.8%	35.5%	37.7%	56.9%	54.6%	55.8%	61.6%	60.5%	61.1%	65.7%	66.8%	66.3%

Table A .1.3

 A Korea -Korean National Health and Examination Survey

			Social inequalities in health-related behaviours:						Chapter 2
			Is the grass greener on the other side?
			Korea		1998			2001			2005
				men	women	total	men	women	total	men	women	total
		Total frequency	2941	3396	6337	2179	2706	4885	1822	2398	4220
			25-39	13.6%	14.4%	14.0%	11.7%	12.7%	12.3%	8.3%	9.0%	8.7%
			30-34	15.4%	15.4%	15.4%	15.4%	16.0%	15.7%	13.7%	15.1%	14.5%
	Age group	35-39 40-44 45-49	16.0% 15.3% 11.1%	15.3% 14.3% 10.9%	15.6% 14.7% 11.0%	16.3% 16.4% 13.3%	16.6% 16.6% 11.7%	16.5% 16.5% 12.4%	13.3% 15.3% 17.0%	14.9% 16.3% 14.3%	14.2% 15.9% 15.5%
			50-54	9.9%	9.6%	9.7%	8.6%	9.4%	9.0%	10.4%	11.2%	10.8%
			55-59	9.6%	10.6%	10.1%	10.1%	8.4%	9.1%	11.9%	9.7%	10.6%
			60-64	9.1%	9.6%	9.4%	8.2%	8.6%	8.4%	10.2%	9.4%	9.7%
	Equivalized income	upper upper middle middle lower middle lower	20.5% 21.8% 21.9% 20.4% 15.4%	25.6% 21.6% 19.1% 18.6% 15.0%	23.3% 21.7% 20.4% 19.4% 15.2%	22.7% 19.4% 22.9% 20.3% 14.7%	28.7% 18.7% 19.7% 18.7% 14.3%	26.0% 19.0% 21.1% 19.4% 14.5%	22.7% 21.5% 20.9% 20.4% 14.4%	27.4% 19.9% 18.6% 18.7% 15.4%	25.4% 20.6% 19.6% 19.5% 15.0%
	Obese	no yes	98.2% 1.8%	96.7% 3.3%	97.4% 2.6%	97.4% 2.6%	96.5% 3.5%	96.9% 3.1%	96.8% 3.2%	96.1% 3.9%	96.4% 3.6%
	Over-	weight	no yes	72.2% 27.8%	70.8% 29.2%	71.4% 28.6%	65.5% 34.5%	70.9% 29.1%	68.5% 31.5%	61.6% 38.4%	70.4% 29.6%	66.6% 33.4%
	BMI	classification	underweight normal overweight obese	3.2% 68.9% 26.1% 1.8%	3.8% 67.0% 25.9% 3.3%	3.5% 67.9% 26.0% 2.6%	2.2% 63.3% 31.9% 2.6%	4.7% 66.1% 25.6% 3.5%	3.6% 64.9% 28.4% 3.1%	2.7% 58.9% 35.2% 3.2%	4.1% 66.2% 25.8% 3.9%	3.5% 63.1% 29.8% 3.6%
	Years of education	6 9 12 16 17	16.8% 15.5% 40.2% 24.2% 3.2%	31.5% 17.5% 35.5% 14.7% 0.8%	24.7% 16.6% 37.7% 19.1% 1.9%	10.5% 14.0% 39.0% 31.3% 5.2%	21.0% 15.4% 41.9% 20.7% 1.1%	16.3% 14.8% 40.6% 25.4% 2.9%	9.9% 12.6% 37.7% 35.0% 4.8%	20.3% 14.1% 39.8% 24.1% 1.8%	15.8% 13.4% 38.9% 28.8% 3.1%
											-101 -

Table A .1.4

 A England -Health Survey for England

	Social inequalities in health-related behaviours: Social inequalities in health-related behaviours:												Chapter 2			Chapter 2
	Is the grass greener on the other side? Is the grass greener on the other side?
	England	men		women 1999	total	men	women 2000	total	men	women 2001	total	men		women 2002	total	men	women 2003	total	men	women 2004	total	men	women 2005	total
	Total Frequency	2190		2494		4684	2186	2520	4706	4261	4976	9237	1971		2531		4502	4025	4745	8770	3027	3689	6716	1950	2342	4292
	England 25-39 25-39 30-34 35-39 40-44 45-49 30-34 Total Frequency 50-54 55-59 Age group 35-39 40-44 45-49 Age group	men 937 11.4% women 1991 10.2% total 1046 1983 14.8% 13.4% 14.1% 14.6% 15.5% 15.1% 13.1% 12.4% 12.8% 14.3% 15.2% 14.8% 12.3% 11.5% 11.9% 13.8% 14.8% 13.2% 15.2% 11.5% 8.9% 15.2% 15.4% 12.4% 13.8% 12.9% 12.1%	men 10.7% 1162 15.6% 12.0% 13.6% 14.3% 14.0% 14.3% 14.2% 10.1% 15.3% 13.2% 12.4%	women 1992 11.0% 1242 15.3% 12.9% 14.1% 14.2% 12.0% 15.2% 12.9% 11.6% 15.0% 13.8% 10.7%	total 11.5% 2404 15.4% 12.5% 13.9% 14.2% 13.0% 14.4% 12.7% 10.7% 15.8% 14.1% 11.9%	men 11.3% 5000 14.2% 14.3% 13.1% 12.9% 14.3% 14.7% 12.8% 11.1% 15.4% 14.0% 11.3%	women 1993 10.4% 5364 14.1% 14.6% 13.9% 13.2% 13.6% 13.4% 13.8% 12.1% 14.8% 13.3% 12.1%	total 10.7% 10364 14.2% 14.4% 13.5% 13.0% 13.9% 12.7% 13.9% 11.6% 15.6% 13.8% 12.3%	men 10.6% women 1994 10.2% total 4557 5073 9630 11.7% men 4536 11.0% women 1995 5108 14.0% 14.3% 14.1% 12.1% 13.6% 15.3% 15.0% 15.1% 15.6% 15.2% 15.1% 14.7% 14.9% 15.1% 13.6% 12.4% 12.8% 12.6% 13.0% 12.9% 12.7% 13.5% 13.1% 12.4% 12.9% 13.0% 12.3% 14.0% 13.3% 13.8% 12.2% 11.8% 12.0% 11.8% 12.1% 11.6% 11.8% 15.2% 15.4% 17.8% 16.7% 13.6% 15.6% 13.4% 14.4% 12.2% 11.6% 11.1% 11.3%	total 9.6% 9644 12.9% 15.4% 14.3% 13.0% 12.7% 12.8% 12.6% 13.9% 13.9% 14.3% 11.9%	men 9.3% 4734 12.1% 14.3% 13.9% 13.9% 14.1% 12.3% 11.7% 14.2% 15.1% 14.7% 11.9%	women 1996 9.4% 5303 12.7% 14.7% 14.7% 12.8% 13.7% 12.6% 12.1% 14.1% 14.5% 14.5% 11.9%	total 11.5% 10037 12.5% 14.6% 14.3% 13.4% 13.9% 15.8% 11.3% 9.8% 15.2% 14.9% 11.7%	men 12.4% women 1997 12.0% total 2514 2867 5381 8.8% men 4484 10.0% women 1998 5221 13.1% 12.6% 12.8% 12.3% 12.4% 13.9% 14.9% 14.4% 14.6% 14.4% 13.9% 13.2% 13.5% 14.4% 14.7% 13.6% 13.5% 13.5% 12.3% 12.4% 13.6% 13.9% 13.8% 13.4% 12.6% 13.6% 14.6% 13.5% 11.3% 12.3% 9.5% total 9705 12.4% 14.5% 14.6% 12.4% 13.0% 10.8% 11.0% 13.4% 11.9% 12.6% 9.8% 9.8% 13.6% 13.3% 13.4% 15.3% 15.3% 12.9% 12.9% 12.9% 15.7% 15.3% 11.9% 14.9% 13.6% 12.4% 12.1% 13.6% 14.1% 13.9%
		50-54 60-64	10.0% 9.7% 10.5%	10.3% 9.6%	10.8% 9.7%	10.8% 9.8%	10.8% 9.0%	10.6% 9.4%	10.8% 10.1%	10.7% 9.4%	10.4% 9.7% 10.3% 10.5% 10.3%	11.4% 8.7%	11.6% 9.5%	11.6% 10.9%	12.0% 10.9%	12.1% 10.9%	12.0% 9.8%	12.1% 10.0%	12.6% 9.9% 12.4% 12.2% 12.8% 11.6% 13.4% 11.8% 13.1%
		55-59 60-64 upper	10.1% 10.7% 9.4% 10.5% 11.0%	10.3% 10.8% 2.1%	9.2% 10.5% 5.5%	9.4% 11.4% 7.8%	9.3% 10.9% 2.1%	10.7% 9.9% 4.8%	9.9% 10.0% 7.8%	10.3% 9.9% 2.7%	9.8% 10.4% 5.0%	9.5% 9.9% 9.1% 9.7% 10.1%	10.2% 10.1% 3.6%	10.5% 9.6% 6.0%	10.4% 9.8% 8.4%	9.6% 10.1% 3.3%	9.4% 9.8% 5.6%	9.5% 9.9% 7.4%	10.1% 9.7% 4.1%	9.8% 9.5% 5.6% 10.0% 9.6% 8.6% 10.4% 9.7%	9.8% 10.3% 3.5%	9.8% 10.3% 5.8%
	Socioeconomic status Socioeconomic status	upper upper middle middle lower middle lower upper middle middle lower middle	7.6% 32.9% 40.8% 14.3% 3.0% 1.8% 26.6% 42.9% 18.5% 31.6% 26.9% 4.5% 29.6% 41.9% 16.5% 6.5% 43.6% 45.9% 12.4% 18.6%	8.6% 30.3% 43.3% 13.3% 4.8% 29.1% 44.8% 15.7%	1.8% 25.7% 47.8% 15.8% 4.0% 32.4% 42.6% 13.2%	5.1% 27.9% 45.6% 14.6% 6.7% 30.1% 43.1% 17.9%	10.0% 30.3% 43.9% 11.7% 5.5% 31.2% 42.9% 15.7%	2.4% 26.6% 44.1% 18.8% 4.2% 33.2% 41.4% 13.4%	6.0% 28.4% 44.0% 15.4% 5.7% 29.8% 42.1% 19.7%	8.3% 29.6% 43.2% 13.8% 5.0% 26.3% 2.3% 44.0% 19.8% 3.5% 5.1% 27.9% 43.6% 17.0% 31.4% 32.1% 30.6% 8.4% 31.1% 42.7% 13.1% 4.9% 31.3% 1.9% 25.6% 46.4% 19.0% 4.3% 41.8% 41.7% 41.8% 41.8% 16.8% 13.5% 19.0% 16.6%	5.0% 28.2% 44.6% 16.2% 3.7% 33.6% 41.0% 13.3%	7.5% 32.3% 42.8% 12.7% 5.2% 32.5% 39.7% 19.2%	2.2% 25.9% 45.0% 19.7% 4.5% 33.0% 40.3% 16.5%	4.7% 29.0% 43.9% 16.4% 4.0% 32.0% 40.2% 16.4%	8.0% 31.3% 42.4% 14.7% 5.0% 31.6% 37.6% 21.6%	2.3% 25.3% 45.3% 19.9% 4.5% 28.1% 5.0% 43.9% 17.5% 4.4% 31.8% 7.2% 42.6% 13.6% 31.8% 35.5% 33.7% 2.4% 25.6% 44.3% 19.7% 5.0% 34.6% 4.7% 28.5% 43.5% 16.9% 4.7% 38.8% 39.1% 40.3% 39.7% 19.3% 12.4% 17.5% 15.2%
		lower	4.5%	10.2%	7.5%	4.5%	8.9%	6.8%	4.1%	8.1%	6.2%	5.0%	7.6%	6.4%	4.7%	7.2%	6.0%	4.7%	7.2%	6.0%	3.6%	7.2%	5.5%	4.7%	7.9%	6.4%
	Ethnicity Obese Ethnicity Obese Over-weight Over-weight	White Black Asian no yes White Black Asian no yes no yes no yes	95.8% 2.0% 2.1% 85.5% 14.5% 94.2% 96.1% 2.0% 1.9% 82.6% 17.4% 94.9% 96.0% 2.0% 2.0% 84.0% 16.0% 1.6% 1.7% 4.1% 3.4% 79.7% 78.2% 20.3% 21.8% 42.7% 54.2% 48.8% 57.3% 45.8% 51.2% 33.1% 44.8% 66.9% 55.2%	95.3% 1.2% 3.5% 86.0% 14.0% 94.6% 1.7% 3.8% 78.9% 21.1% 39.9% 60.1% 39.3% 60.7%	96.1% 1.7% 2.2% 82.0% 18.0% 94.2% 1.4% 4.4% 77.3% 22.7% 53.5% 46.5% 29.2% 70.8%	95.7% 1.5% 2.8% 83.9% 16.1% 94.4% 1.7% 3.9% 78.8% 21.2% 47.0% 53.0% 45.9% 54.1%	95.2% 1.8% 3.0% 85.3% 14.7% 94.3% 1.6% 4.1% 78.1% 21.9% 38.3% 61.7% 38.1% 61.9%	95.3% 2.0% 2.7% 82.7% 17.3% 94.8% 1.4% 3.8% 77.2% 22.8% 50.9% 49.1% 28.5% 71.5%	95.3% 1.9% 2.9% 83.9% 16.1% 95.0% 1.8% 3.2% 75.2% 24.8% 44.8% 55.2% 42.7% 57.3%	95.2% 1.4% 3.4% 85.0% 15.0% 94.9% 95.4% 2.1% 2.5% 82.3% 17.7% 94.1% 95.3% 1.7% 2.9% 83.6% 16.4% 94.1% 95.4% 1.3% 3.3% 83.1% 16.9% 94.1% 95.6% 1.6% 2.8% 81.8% 18.2% 1.6% 1.4% 2.1% 1.8% 3.5% 4.5% 3.9% 4.1% 76.2% 76.0% 76.0% 76.0% 23.8% 24.0% 24.0% 24.0% 38.6% 51.2% 45.3% 36.8% 49.2% 61.4% 48.8% 54.7% 63.2% 50.8% 36.2% 29.5% 42.5% 36.8% 63.8% 70.5% 57.5% 63.2%	95.5% 1.5% 3.0% 82.4% 17.6% 93.6% 1.9% 4.5% 75.7% 24.3% 43.4% 56.6% 28.8% 71.2%	94.6% 1.8% 3.6% 81.8% 18.2% 94.0% 2.0% 4.0% 76.2% 23.8% 34.4% 65.6% 42.6% 57.4%	94.8% 2.2% 3.0% 80.9% 19.1% 93.8% 2.0% 4.2% 76.0% 24.0% 47.0% 53.0% 36.3% 63.7%	94.7% 2.0% 3.3% 81.3% 18.7% 58.3% 13.2% 28.4% 78.4% 21.6% 41.0% 59.0% 33.3% 66.7%	94.3% 1.7% 4.1% 81.0% 19.0% 60.9% 14.3% 24.8% 74.2% 25.8% 33.4% 66.6% 39.7% 60.3%	94.8% 1.9% 3.3% 79.3% 20.7% 59.8% 94.6% 1.8% 3.6% 80.1% 19.9% 93.6% 95.0% 2.1% 2.9% 81.2% 18.8% 93.9% 95.4% 1.9% 2.7% 78.3% 21.7% 93.8% 95.2% 2.0% 2.8% 79.6% 13.8% 1.1% 1.8% 1.5% 26.4% 5.2% 4.3% 4.7% 76.1% 74.2% 74.5% 74.3% 23.9% 25.8% 25.5% 25.7% 20.4% 46.9% 40.6% 33.0% 45.5% 39.7% 53.1% 59.4% 67.0% 54.5% 60.3% 36.8% 28.5% 41.8% 35.7% 63.2% 71.5% 58.2% 64.3%
	BMI classification BMI classification	under-weight normal over-weight obese under-weight normal over-weight obese	1.2% 41.5% 42.8% 14.5% 0.7% 2.0% 52.2% 28.4% 17.4% 32.4% 43.7% 1.6% 47.2% 35.2% 16.0% 1.1% 46.6% 33.4% 20.3% 21.8%	0.9% 39.1% 46.0% 14.0% 0.9% 38.4% 39.6% 21.1%	2.0% 51.5% 28.5% 18.0% 0.5% 28.6% 48.1% 22.7%	1.5% 45.5% 37.0% 16.1% 1.3% 44.6% 33.0% 21.2%	0.7% 37.5% 47.0% 14.7% 0.9% 37.2% 40.0% 21.9%	1.4% 49.5% 31.8% 17.3% 0.6% 28.0% 48.7% 22.8%	1.1% 43.7% 39.1% 16.1% 1.1% 41.6% 32.5% 24.8%	0.6% 38.1% 46.4% 15.0% 0.9% 49.6% 1.6% 31.1% 17.7% 0.7% 1.1% 44.2% 38.3% 16.4% 35.3% 28.8% 41.4% 0.7% 36.2% 46.3% 16.9% 1.1% 35.9% 1.4% 47.8% 32.6% 18.2% 0.9% 40.0% 46.5% 33.5% 39.2% 23.8% 24.0% 24.0% 24.0%	1.0% 42.3% 39.0% 17.6% 0.6% 28.3% 46.8% 24.3%	0.6% 33.8% 47.4% 18.2% 1.1% 41.5% 33.6% 23.8%	1.2% 45.9% 33.9% 19.1% 0.9% 35.4% 39.7% 24.0%	0.9% 40.2% 40.3% 18.7% 0.9% 32.4% 45.1% 21.6%	0.3% 33.1% 47.6% 19.0% 1.2% 38.4% 34.5% 25.8%	1.5% 45.4% 32.4% 20.7% 1.1% 39.6% 0.9% 39.5% 19.9% 0.3% 32.4% 0.6% 48.2% 18.8% 35.7% 28.3% 40.7% 1.2% 44.3% 32.8% 21.7% 1.0% 35.1% 0.9% 38.8% 39.9% 20.4% 0.7% 39.3% 45.6% 32.7% 38.6% 23.9% 25.8% 25.5% 25.7%
		8	11.4%	12.0%	11.7%	10.2%	9.3%	9.7%	8.5%	8.2%	8.3%	7.5%	6.8%	7.1%	6.7%	5.5%	6.1%	5.0%	5.2%	5.1%	3.7%	4.4%	4.1%	2.8%	2.8%	2.8%
	Years of education Years of education	9 10 11 12 13 15 10 8 9 11 12 13	30.6% 27.2% 7.7% 5.1% 5.7% 12.3% 3.2% 29.3% 26.9% 9.3% 10.0% 6.8% 5.8% 26.2% 26.9% 29.9% 27.0% 8.5% 7.7% 6.3% 8.9% 2.8% 32.3% 31.2% 6.7% 10.1% 7.7% 10.0% 8.6% 8.3%	28.4% 28.8% 7.0% 6.7% 7.7% 11.3% 3.0% 26.6% 31.7% 8.5% 8.9% 8.5%	29.9% 28.8% 9.2% 10.0% 6.0% 6.8% 3.2% 24.1% 30.6% 8.2% 7.2% 10.7%	29.2% 28.8% 8.1% 8.4% 6.8% 8.9% 2.3% 21.1% 32.4% 9.4% 11.7% 10.6%	27.7% 29.4% 7.5% 7.2% 6.9% 12.9% 2.8% 22.5% 31.6% 8.9% 9.6% 10.6%	29.2% 27.7% 8.7% 9.4% 8.9% 7.8% 2.6% 23.2% 31.9% 7.8% 8.1% 10.0%	28.5% 28.5% 8.1% 8.3% 8.0% 10.3% 2.2% 23.7% 32.1% 9.9% 11.3% 9.7%	25.2% 31.6% 7.5% 7.5% 8.3% 12.5% 2.4% 27.8% 28.4% 10.0% 10.2% 8.2% 8.7% 2.4% 26.5% 29.9% 8.8% 8.9% 8.2% 10.5% 23.4% 22.0% 22.0% 27.3% 30.6% 8.1% 7.5% 19.8% 0.1% 1.8% 22.0% 29.1% 29.3% 10.0% 10.0% 16.0% 0.1% 2.0% 32.0% 32.8% 29.7% 31.1% 9.0% 7.5% 9.7% 8.7% 9.8% 8.7% 11.8% 10.4% 9.8% 10.1% 11.2% 10.7%	28.2% 29.9% 9.1% 8.8% 17.8% 0.1% 2.4% 21.4% 32.4% 7.2% 8.8% 10.1%	26.8% 31.8% 7.5% 7.3% 21.4% 0.2% 1.9% 21.7% 30.9% 9.7% 11.4% 10.5%	26.7% 31.4% 10.1% 9.3% 17.3% 0.1% 2.1% 21.6% 31.6% 8.5% 10.2% 10.3%	26.7% 31.6% 8.8% 8.3% 19.2% 0.1% 3.9% 14.7% 25.4% 7.8% 9.1% 16.4%	26.0% 31.5% 7.9% 8.5% 8.5% 14.0% 5.4% 15.7% 25.0% 9.8% 11.6% 14.8%	29.1% 30.1% 9.4% 10.1% 7.1% 9.8% 4.7% 27.6% 30.7% 8.7% 9.4% 7.7% 11.8% 2.2% 27.8% 32.2% 7.5% 7.1% 8.4% 14.1% 15.3% 20.0% 19.8% 27.1% 31.8% 9.4% 11.0% 8.0% 9.8% 1.6% 19.9% 27.4% 32.0% 8.5% 9.2% 8.2% 11.8% 1.9% 25.2% 30.6% 30.8% 30.7% 8.9% 7.6% 10.7% 9.3% 10.5% 8.9% 11.6% 10.3% 15.5% 11.2% 9.1% 10.0%
		15	15.2%	10.7%		12.8%	15.9%	12.4%	14.0%	16.4%	11.2%	13.6%	16.5%	13.8%	15.0%	17.7%	13.9%	15.6%	22.7%	17.7%	20.0%	19.6%	16.5%	17.9%
															-102 -
											-103 -

BMI Annex 3. Regression analysis related to estimates in Figures 4 to 6

  Linear regression was used to estimate BMI level associated with different lengths of time in education for both genders.Logistic regression was used to estimate the likelihood of obesity associated with different lengths of time in education for both genders and by ethnicity/minority status.

	Odds ratios Significance ref. 1.287 *** 1.325 *** 1.450 *** 1.717 *** 1.752 *** 1.604 *** 1.536 *** 1.062 *** 1.027 Years of education -Men Age 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 Year of survey Women 8 ref. 12 0.738 *** 14 0.568 *** Years of education -Women 8 ref. 12 0.700 *** 14 0.462 *** SES highest ref. middle-high 1.157 *** middle 1.132 *** middle-low 1.517 *** lowest 1.381 *** Obs. 67671 Prob > chi2 0.000 Pseudo R2 0.032 Australia Dependant variable: obesity status England Dependant variable: obesity status Estimates Significance Australia Dependant variable: BMI Odds ratios Significance Age 1.064 *** Age squared 0.999 *** Year of survey 1.058 *** Women 1.368 *** Years of education -Men 8 ref. 9 0.956 10 0.882 ** 11 0.788 *** 12 0.726 *** 13 0.706 *** 15 0.558 *** Years of education -Women 8 ref. 9 0.792 *** 10 0.677 *** 11 0.599 *** 12 0.565 *** 13 0.558 *** 15 0.353 *** SES highest ref. middle-high 1.235 *** middle 1.199 *** middle-low 1.347 *** lowest 1.440 *** Obs. 104143 Prob > chi2 0.000 Pseudo R2 0.0266 Age 25-29 ref. 30-34 0.523 *** 35-39 0.695 *** 40-44 1.006 *** 45-49 1.422 *** 50-54 1.575 *** 55-59 1.575 *** 60-64 1.454 *** Year of survey 0.123 *** Women -0.554 *** Years of education -Men 8 ref. 12 -0.351 *** 14 -0.883 *** Years of education -Women 8 ref. 12 0.239 *** 14 0.867 *** SES highest ref. middle-high 0.184 *** middle 0.143 ** middle-low 0.538 *** lowest 0.254 *** Obs. 67671 Prob > F 0.000 Pseudo R2 0.0709 Estimates Significance Age 0.183 *** Age squared -0.001 *** Year of survey 0.120 *** Women 0.503 *** England Dependant variable: BMI highest ref. SES 14 0.576 *** 12 0.693 * Age 25-29 ref. 30-34 1.259 ** 35-39 1.396 *** 40-44 1.559 *** 45-49 1.715 *** 50-54 1.735 *** 55-59 1.475 *** 60-64 1.435 *** Year of survey 1.070 *** Years of education -Migrant 8 ref. 12 0.580 *** 14 0.373 *** Years of education -Non-migrant 8 ref. Dependant variable: Table A.3.1: Australia Odds ratios Significance Age 25-29 ref. 30-34 1.091 * 35-39 1.140 *** 40-44 1.180 *** 45-49 1.391 *** 50-54 1.538 *** 55-59 1.543 *** 60-64 1.490 *** Year of survey 1.039 *** Women 0.956 Years of education -Men 8 ref. 12 0.848 *** 14 0.867 ** 17 0.709 *** Years of education -Women 8 ref. 12 0.754 *** 14 0.896 17 0.599 *** SES highest ref. middle-high 1.141 *** middle 1.136 *** middle-low 1.151 *** lowest 1.207 *** Obs. 219496 Prob > chi2 0.000 Pseudo R2 0.0124 Canada Dependant variable: obesity status Korea Dependant variable: obesity status Estimates Dependant variable: BMI Canada Significance Age Odds ratios Significance Age 0.973 Age square 1.000 Year of survey 1.066 *** Women 3.968 *** Years of education -Men 6 ref. 9 1.601 12 1.649 16 1.509 17 1.909 Years of education -Women 6 ref. 9 1.007 12 0.418 *** 16 0.195 *** 17 1.3E-07 *** SES highest ref. middle-high 0.967 middle 1.001 middle-low 1.055 lowest 1.217 Obs. 15242 Prob > chi2 0.000 Pseudo R2 0.026 25-29 ref. 30-34 0.496 *** 35-39 0.651 *** 40-44 0.847 *** 45-49 1.303 *** 50-54 1.638 *** 55-59 1.733 *** 60-64 1.552 *** Year of survey 0.078 *** Women -0.749 *** Years of education -Men 8 ref. 12 -0.128 14 -0.140 17 -0.506 *** Years of education -Women 8 ref. 12 -0.801 *** 14 -0.725 *** 17 -1.398 *** SES highest ref. middle-high 0.148 *** middle 0.057 middle-low 0.036 lowest -0.091 Obs. 219496 Prob > F 0.000 Pseudo R2 0.0514 Estimates Age Age square Year of survey Women 1.300 *** highest ref. 0.065 *** SES -0.002 *** 14 0.729 *** 0.223 *** 12 0.878 Significance Korea Age 25-29 ref. 30-34 1.369 *** 35-39 1.347 *** 40-44 1.479 *** 45-49 1.927 *** 50-54 1.998 *** 55-59 1.969 *** 60-64 1.841 *** Year of survey 1.050 *** Years of education -Migrant 8 ref. 12 0.675 *** 14 0.408 *** Years of education -Non-migrant 8 ref. Odds ratios Significance Australia -men Dependant variable: obesity status Odds ratios Significance Dependant variable: Australia -women obesity status
	Years of education -Men 8 9 10 11 middle-high middle middle-low lowest	ref. 0.027 -0.071 -0.312 ** 1.115 * 0.973 1.389 *** 1.170 **	Years of education -Men 6 middle-high 1.247 *** ref. 9 middle 1.409 *** 0.487 *** 12 middle-low 1.784 *** 0.739 *** 16 0.922 *** lowest 1.760 ***
	12 13 15 Years of education -Women -0.390 *** -0.569 *** -0.948 *** Obs. 33523 Prob > chi2 0.000 Pseudo R2 0.0357	17 Obs. Years of education -Women 1.379 *** 34148 6 Prob > chi2 0.000 ref. 9 0.042 Pseudo R2 0.0367
	8 9 10 11 12 13 15		ref. -0.603 *** -1.028 *** -1.401 *** -1.598 *** -1.622 *** -2.647 ***	12 16 17 highest middle-high SES middle		-1.167 *** -2.223 *** -2.584 *** ref. -0.184 ** -0.104
	SES middle-high highest middle middle-low lowest		ref. 0.332 *** 0.196 *** 0.434 *** 0.467 ***	middle-low lowest Obs. Prob > F Pseudo R2	15704 0.000 0.0806	-0.124 -0.294 ***
	Obs.	104143
	Prob > F	0.000
	Pseudo R2	0.0503

Table A .3.2. Canada

 A

	Canada -men	Odds ratios Significance Dependant variable: obesity status	Canada -women	Odds ratios Significance Dependant variable: obesity status
	Age		Age
	25-29	ref.	25-29	ref.
	30-34	1.222 ***	30-34	1.193 ***
	35-39	1.203 ***	35-39	1.160 ***
	40-44	1.197 ***	40-44	1.210 ***
	45-49	1.366 ***	45-49	1.441 ***
	50-54	1.471 ***	50-54	1.689 ***
	55-59	1.475 ***	55-59	1.646 ***
	60-64	1.323 ***	60-64	1.474 ***
	Year of survey	1.030 ***	Year of survey	1.053 ***
	Years of education -Non-minority	Years of education -Non-minority
	8	ref.	8	ref.
	12	0.880 ***	12	0.823 ***
	14	0.869 ***	14	0.843 ***
	17	0.735 ***	17	0.739 ***
	Years of education -Minority	Years of education -Minority
	8	ref.	8	ref.
	12	0.639 ***	12	0.529 ***
	14	0.761 ***	14	0.926
	17	0.467 ***	17	0.549 ***
	SES		SES
	highest	ref.	highest	ref.
	middle-high	0.988	middle-high	1.323 ***
	middle	0.941 **	middle	1.554 ***
	middle-low	0.944	middle-low	1.825 ***
	lowest	0.875 ***	lowest	1.821 ***
	Obs.	101113	Obs.	106698
	Prob > chi2	0.000	Prob > chi2	0.000
	Pseudo R2	0.0075	Pseudo R2	0.0179

Table A .3.3. England

 A

	Social inequalities in health-related behaviours:		Chapter 2
	Is the grass greener on the other side?
	England-men	Odds ratios Significance Dependant variable: obesity status	England-women	Odds ratios Significance Dependant variable: obesity status
	Age	1.089 ***	Age	1.042 ***
	Age squared	0.999 ***	Age squared	1.000 ***
	Year of survey	1.067 ***	Year of survey	1.050 ***
	Years of education -White	Years of education -White
	8	ref.	8	ref.
	9	0.869 **	9	0.886 **
	10	0.781 ***	10	0.774 ***
	11	0.701 ***	11	0.696 ***
	12	0.626 ***	12	0.656 ***
	13	0.640 ***	13	0.615 ***
	15	0.471 ***	15	0.414 ***
	Years of education -Black	Years of education -Black
	8	ref.	8	ref.
	9	0.517 ***	9	1.631 ***
	10	0.618 ***	10	1.650 ***
	11	0.537 **	11	1.582 ***
	12	0.664	12	1.396 **
	13	0.677 **	13	1.862 ***
	15	0.634 **	15	0.984
	Years of education -Asian	Years of education -Asian
	8	ref.	8	ref.
	9	0.517 ***	9	1.631
	10	1.169 ***	10	1.142
	11	0.970 ***	11	0.704 ***
	12	1.153 ***	12	0.831 ***
	13	0.826 ***	13	0.762 ***
	15	0.762 ***	15	0.615 ***
	SES		SES
	highest	ref.	highest	ref.
	middle-high	1.220 ***	middle-high	1.378 ***
	middle	1.185 ***	middle	1.347 ***
	middle-low	1.135 **	middle-low	1.682 ***
	lowest	1.022	lowest	1.930 ***
	Obs.	48558	Obs.	55585
	Prob > chi2	0.000	Prob > chi2	0.000
	Pseudo R2	0.0261	Pseudo R2	0.0312
		-109 -

Table 2 .

 2 . A single factor is defined for all genders and age groups since aggregate APC data are not available by gender and age. While aggregate data are calculated for population above age 15, survey data may cover different age groups (e.g. people aged 25-74 in Finland). More detail on the correction procedure is available in Annex 1. Once the correction is applied, new WCIs are computed. Factor of correction Note: (*) Survey data in the UK refers to England only.

with less education more likely to drink at risk People with more education more likely to drink at risk

	3 People with more education -0.2 -0.1 People Social inequalities in health-related behaviours: 0.0 0.1 0.2 0.3 Canada England Germany USA Ireland France Finland Spain Hungary Switzerland New Zealand Japan Korea After correction Before correction People with less education -0.3 -0.2 -0.1 0.0 0.1 England Hungary France Canada USA Spain Germany New Zealand Switzerland Ireland Finland Japan Korea After correction 0.2 0.3 Before correction Chapter 3 Is the grass greener on the other side?
	more likely to drink at risk	more likely to drink at risk
		-120 -

  Marital status is classified into Married /Single /Other. Working status is defined as Working /Not working. Smoking is categorised into Current /Ex-/Never smoker. International standard classifications, such as ISCED for education and ISCO for occupation, were used to deal with the data heterogeneity issue. Education level is recoded into three

	groups: low (ISCED 0, 1, 2) / medium (3, 4) / high (5, 6). An attempt was made to standardise different
	occupation-based SES, by recoding occupations as: lowest (unskilled manual) / middle-low (semi-skilled
	manual) / middle (skilled manual, non-manual) / middle-high (managerial technical) / highest
	(professional). Five-level occupation-based SES variable was available or could be derived in England,

  ). Since the studied outcome "hazardous drinking" is a negative health outcome, the education (and SES) ladder is ranked from the highest to the lowest level, in order to facilitate the interpretation of the index. The CI of a health variable Y is computed using the simple convenient covariance formula (O'Donnell, Van Doorslaer,

	Social inequalities in health-related behaviours:	Chapter 3
	Is the grass greener on the other side?
	Wagstaff, & Lindelow, 2008):

μ he e μ is the eighted sa ple ea of Y, o w denotes the weighted covariance and R i is the relative fractional rank of the i th individual in the education level distribution. The standard errors computed for

Table 1 .

 1 List of survey data Note: n.a. means not available. (a) Visits in the past 24 months; (b) Visits in the past 12 months

	Social inequalities in health-related behaviours:

Table 2 .

 2 Health system features Note: N.A. not available. The total current health expenditure (TCHE) comprises public expenditure, private insurance, household out-of-pocket as well as nonprofit institutions serving households and corporations (other than health insurance).

	Source: OECD Health Statistics 2013 [ ]; Autho s i fo atio ased o OECD Health System Characteristics surveys 2008 and 2012 [19]; OECD, 2013
	[20]

  Is the grass greener on the other side?

	Social inequalities in health-related behaviours:																				Chapter 4
		0.40																	0.40
		0.30																	0.30
	Inequality index	0.00 0.10 0.20																Inequality index	0.00 0.10 0.20
		-0.10																	-0.10
		0.20	Slovenia	United Kingdom	Slovak Republic	Switzerland	Austria	Spain	Hungary	Poland	Czech Republic	Canada	New Zealand	Ireland*	France	Estonia	Belgium	United States	-0.20	Slovak Republic	Slovenia	Ireland*	Switzerland	Estonia	United Kingdom	Hungary	Austria	Canada	Poland	Spain	United States	New Zealand	Czech Republic	France	Belgium

Socioeconomic status here refers to income or occupation.

This discussion leaves apart genetic factors, as they are not generally in the action target of governments. However it is worth noting that more and more attention is paid to the genomics, the science of genomic sequences, that is promising in the coming years to help to detect and prevent diseases such as cancers and cardio-vascular diseases.

[START_REF] Van Kippersluis | al ool e F a e: uelles so t les populations à risque ? IRDES Questio d'Éco o ie de la Santé 129[END_REF] assume that the decision to engage in unhealthy consumption is governed by the monetary cost of the good and the health cost related to the consumption of the good (i.e. value of health lost). They assume that wealth influences health behaviours via two competing effects: the direct wealth effect that increases the demand for (unhealthy) consumption goods; and the indirect health cost effect that decreases the demand for unhealthy consumption goods (since the health cost is higher for those who invest in health i.e. the more affluent).

When inequality in health care utilisation remains after adjusting for the level of health care needs, we talk about inequity.

This thesis assembles four pieces of applied micro-economics research that focus on (i) obesity and overweight, (ii) risky alcohol consumption, and (iii) health care services utilisation. These four studies are based on health survey data for a number of countries. The first part of this chapter presents the data sources used, issues of cross-country comparability and survey data limitations. The second part of this chapter describes the methodological approaches applied to measuring inequalities in a cross-country perspective.

The WHO uses four risk drinking groups founded on epidemiological evidence. The first group refers to abstainers. Category I indicates drinkers at low risk (below 20g of pure alcohol daily for women and 40g for men). Category II consists of alcohol use at isk fo health ≥ -g fo o e a d ≥ -60g for men). Category III consists of alcohol consumption that is already causing ha to the d i ke , ho a also ha e s pto s of depe de e ≥ g fo o e a d ≥ g fo e .

To perform international comparisons, the same age range and frequency was adopted as that used for the OECD Health Data collection.

We tested whether this distinction in the construction of the variable had an effect on obesity status by introducing a control dummy variable, but it was not significant.

A half-pint of beer, a glass of wine, a shot of whisky are all examples of one standard drink. A standard drink contains the same amount of alcohol regardless of the container size or the type of alcoholic beverage. However the definition of a standard drink differs across countries. For instance, the content of a standard drink is 13.6 grams of pure alcohol in Canada, 14 grams in USA and 10 grams in France.

Chapter 2.

Social inequalities in obesity and overweight in eleven OECD countries Marion Devaux,Franco Sassi European Journal of Public Health,Vol. 23,No. 3,[464][465][466][467][468][469].

Supplementary File No.2 -Trends in obesity and overweight rates by level of education

As data for Austria, Hungary and Sweden cover one or two survey years, they were not taken into account in the analysis of trends.

Inequalities over time were first analysed graphically. In most countries, trends in obesity and overweight by level of education are broadly parallel. However it is worth noting exceptions for men in England and in Korea, where inequalities appear to have decreased. Additionally, an overall interaction Wald-test for the significance of the interaction term between time and education reveals that the interaction term is significant in England and Italy for overweight in men, in Italy for obesity in women and in England and France for obesity and overweight in women. In England, results suggest a reduction in inequalities across education levels. (Figures A3-A5 Panel A). In Italy, inequalities in overweight for men appear to increase over time, but at a small degree (Figure A7 Reported rates are estimates from logistic regression models adjusted for a range of demographic and socio-economic covariates (age, smoking status, occupation status, marital status, education level, socioeconomic condition, and ethnicity for England and the US). Rates are relative to people aged 40, non smoking, working and married. Darker lines represent the lowest level of education. Estimated rates of obesity and overweight controlled for socio-demographic covariates, are displayed for men and women separately. Moreover, results were broken down by ethnicity for England and the US as the data provide that information.

ABSTRACT

An epidemic of obesity has been developing in virtually all OECD countries over the last 30 years.

Existing evidence provides a strong suggestion that such an epidemic has affected certain social groups more than others. In particular, a better education appears to be associated with a lower likelihood of obesity, especially among women. This paper sheds light on the nature and the strength of the correlation between education and obesity. Analyses of health survey data from Australia, Canada, England, France, and Korea were undertaken with the aim of exploring this relationship. Social gradients in obesity were assessed across the entire education spectrum, overall and in different population subgroups. Furthermore, investigations testing for mediation effects and for the causal nature of the links observed were undertaken to better understand the underlying mechanisms of the relationship between education and obesity. and measures the proportion of the total variance which is between-groups. The same correlation index in case of random coefficient models equals

The existence of a non-zero intra-group correlation indicates that traditional estimation procedures used in multiple regressions, such as ordinary least square, are not correct. For this reason, estimation methods for multilevel models include generalized least square techniques [START_REF] Goldstein | Social inequalities in health-related behaviours: Chapter 2 Is the grass greener on the other side[END_REF], Fisher scoring algorithm [START_REF] Longford | A Fast Scoring Algorithm for Maximum Likelihood Estimation in Unbalanced Mixed Models with Nested Random Effects[END_REF] or the expectation-maximization algorithm [START_REF] Raudenbush | A Hierarchical Model for Studying School Effects[END_REF]. The simple 2-level random coefficient model in ( 5) can be further extended by introducing more explanatory variables at either the individual or the group levels. Moreover, the number of nested levels can be increased when considering more aggregation stages.

In the case y ij is a discrete response, the model is a hierarchical logistic model and the random intercept model is

with e ij having logistic distribution and the individual-le el a ia e σ 2

e is e ual to π 2 /3. So, the intra-class o elatio is ith σ 2 u0 the group-level variance)

ABSTRACT

Background: Self-report bias in surveys of alcohol consumption is widely documented, however, less is known about the distribution of such bias by socioeconomic status (SES) and about the possible impact on social disparities. This study aims to assess how correcting alcohol consumption data for self-report bias may affect estimates of social disparities in hazardous drinking (HD).

Methods: National survey data from 13 countries: Canada, England, Finland, France, Germany, Hungary, Ireland, Japan, Korea, New Zealand, Spain, Switzerland and USA, are used to examine social disparities in HD by SES and education level. Defining HD as drinking above 3 drinks per day for men, and 2 for women, social disparities were assessed by calculating country-level concentration indexes. Aggregate consumption data were used to correct survey-based estimates for self-report bias.

Results: Survey data show that more-educated women are more likely than less-educated women to engage in HD, while the opposite is observed in men in most countries. Large discrepancies in alcohol consumption between survey-based and aggregate estimates were found. Correcting for self-report bias increased estimates of social disparities in women, and decreased them in men, to the point that gradients were reversed in several countries (from higher rates in low education/SES men to an opposite pattern).

Conclusion:

This study provides evidence of a likely mis-estimation of social disparities in HD, in both men and women, due to self-report bias in alcohol consumption surveys. This study contributes to a better knowledge of the social dimensions of HD and to the targeting of alcohol policies.

Country

ABSTRACT

A key policy objective in OECD countries is to achieve adequate access to health care for all people on the basis of need. Previous studies have shown that there are inequities in health care services utilisation (HCSU) in the OECD area. In recent years, measures have been taken to enhance health care access. This paper re-examines income-related inequities in doctor visits among 18 selected OECD countries, updating previous results for 12 countries with 2006-2009 data, and including six new countries.

Inequalities in preventive care services are also considered for the first time. The indirect standardisation procedure is used to estimate the need-adjusted HCSU and concentration indexes are derived to gauge inequalities and inequities.

Overall, inequities in HCSU remain present in OECD countries. In most countries, for the same health care needs, people with higher incomes are more likely to consult a doctor than those with lower incomes.

Pro-rich inequalities in dental visits and cancer screening uptake are also found in nearly all countries, although the magnitude of these varies among countries. These findings suggest that further monitoring of inequalities is essential in order to assess whether country policy objectives are achieved on a regular basis.

Germany

German Telephone Health Interview Survey (GEDA) 2009 Social inequalities in health-related behaviours:

Chapter 4 Is the grass greener on the other side? -138 -

HCSU variables

Three types of health care services were analysed, these being: (i) doctor visits (separate GP and specialist); (ii) dentist visits; and (iii) breast and cervical cancer screening services for women. The probability of having a medical visit at least once in the past 12 months is measured for contacts with a doctor and a dentist in all countries (with the exception of dental visits in the past 24 months in France).

National guidelines relating to cancer screening may differ across countries, affecting the inclusion age and frequency of visit. To perform international comparisons, the same age range and frequency were adopted as those used by international research groups [START_REF] Grittner | Social Inequalities and Gender Differences in the Experience of Alcohol-Related Problems[END_REF][START_REF] Stockwell | Under-reporting of alcohol consumption in household surveys: A comparison of quantity-frequency, graduated-frequency, and recent recall[END_REF]. For breast cancer screening, the focus was on women aged 50-69 years who reported having a mammogram in the past 2 years, and for cervical cancer screening, women aged 20-69 years who had a Pap smear test in the past 3 years. The recall period for cancer screening in Ireland referred to the past 12 months.

Table 1 provides the survey name, the sample size, and the probability of HCSU in the 18 countries studied. Further information on the variables of interest is displayed in the web appendix Table A1.

Need-adjustment

Persons in lower socioeconomic groups have higher rates of morbidity, and have greater needs for health care [3,[START_REF] Boniface | How is alcohol consumption affected if we account for underreporting? A hypothetical scenario[END_REF]. Doctor, GP and specialist visits are thus adjusted to remove the effect of differing needs for care among persons with different income levels, so that the horizontal equity principle can be tested, as this was previously applied [4,5].

Let Y be the HCSU and X a set of health care need variables. The indirect standardisation procedure as des i ed i O Do ell et al. [START_REF] Meier | Adjusting for unrecorded consumption in survey and per capita sales data: Quantification of impact on gender-and age-specific alcohol-attributable fractions for oral and pharyngeal cancers in Great Britain[END_REF], is used to estimate the need-adjusted HCSU, Y IS .

where is Y X i , is the need-predicted utilisation and Y mean the sample mean.

The need-predicted HCSU, Y X i , i.e. the expected utilisation if all individuals used health care services on the basis of their needs, is predicted for each individual i by regressing the actual utilisation Y i on a set of need variables on one hand, and non-need variables which are fixed at the sample mean on the other hand. A logit link function is used for the regression model. The need variables correspond to a range of indicators Social inequalities in health-related behaviours: Chapter 4 Is the grass greener on the other side? -139 -including age, gender, self-assessed health and limitations in daily activities. Controlling for a range of socio-demographic non-need variables permits to accurately estimate the need-HCSU relationship. We follow Van Doorslaer et al. [4,5] and control for ethnicity, education level, marital status and private insurance status 18 -that may affect the efficiency of health production and the propensity to seek care-, and for activity status, region and level of urbanisation -that may affect time price of HCSU. A description of the variables used for the need-adjustment procedure is provided in the web appendix Table A1.

This study also assesses income-related inequalities in dentist visits and breast and cervical cancer screening uptake, however the need-adjustment is not performed for two reasons. First, an annual dental visit being recommended for all persons in most countries, and cancer screening being recommended for women in the targeted age group, one can assume equal needs for preventive care. Second, most data sources do not systematically provide information on needs for curative dental care, that technically prevents from adjusting for needs.

Income

Equivalised household income is used as the ranking variable. Data correspond to household total income from all sources after tax and deductions, except in New Zealand and the United Kingdom where income is before tax. Effort is made to equivalise household income with the OECD modified scale in order to a ou t fo diffe e es i household s size and composition, though the equivalisation procedure somewhat differs across countries due to data limitations. For countries where income is a continuous variable, the equivalised household income is consistently derived (Finland, France, Germany, Spain, Switzerland, UK, and USA). For countries where household income is categorised into brackets or deciles, two approaches are used. If the income brackets mid-points are available, the equivalised income is derived using the mid-point value and the size of the household (Ireland and New Zealand). If not, the equivalised income is derived by crossing data from income categories and the size of the household (Canada and EHIS countries) 19 . 18 Although the inclusion of private health insurance in the specification of the model may create an endogeneity problem due to selection effect, a sensitivity analysis showed that the findings were robust. We replicated the analysis without including insurance and found that the overall results for the measure of inequities were unchanged.