PhD Lucía Artazcoz
email: lartazco@aspb.cat]

Imma Cortès

PhD Vicenta Escribà-Agüir

MD Lorena Cascant

MPH Rodrigo Villegas

UNDERSTANDING THE RELATIONSHIP OF LONG WORKING HOURS WITH HEALTH STATUS AND HEALTH-RELATED BEHAVIOURS Running title: Long working hours and health

Keywords: Long working hours, gender, mental health, hypertension, smoking, sleep

Background:

The objectives of this study are to identify family and job characteristics associated with long workhours, to analyse the relationship between long workhours and several health indicators and to examine whether gender differences for both objectives exist.

Methods:

The sample was composed of all salaried workers aged 16-64 years (3950 men and 3153 women) interviewed in the 2006 Catalonian Health Survey. Weekly workhours were categorized as less than 30 hours (part-time), 30-40 (reference category), 41-50 and 51-60 hours. Multiple logistic regression models separated by sex were fitted.

Results: Factors associated with long working hours differed by gender. Among men extended workhours were related with being married or cohabiting and with being separated or divorced. In males, working 51-60 hours a week was consistently associated with poor mental health status (aOR=2.06, 95% CI=1.31-3.24), self-reported hypertension (aOR=1.60, 95% CI=1.12-2.29), job dissatisfaction (aOR=2.05, 95% CI=1.49-2.82), smoking (aOR=1.33, 95% CI=1.03-1.72), shortage of sleep (aOR=1.42, 95% CI=1.09-1.85) and no leisure-time physical activity (aOR=2.43, 95% CI=1.64-3.60). Moreover, a gradient from standard working hours to 51-60 hours a week was found for these six outcomes. Among women it was only related to smoking and to shortage of sleep.

Conclusion:

The association of overtime with different health indicators among men could be explained by their role of family breadwinners that in situations of family financial stress can derived into pressure to work overtime in order to increase the income and/or acceptance of poor working conditions, one of them being long working hours, due to fear of job loss.

INTRODUCTION

Although in recent years interest in health problems related to long working hours has intensified, the number of studies concerning the different areas of health is still low and the results are often contradictory. [START_REF] Harrington | Working long hours and health[END_REF][START_REF] Spurgeon | Health and safety problems associated with long working hours: a review of the current positions[END_REF][START_REF] Caruso | Overtime and extended work shifts: Recent findings on illnesses, injuries and health behaviors[END_REF][START_REF] Van Der Hulst | Long workhours and health[END_REF] The inconsistent findings can be related to several methodological shortcomings of previous research, including small sample sizes or unique industry specific circumstances [START_REF] Proctor | Effect of overtime work on cognitive function in automotive workers[END_REF][START_REF] Borg | Psychosocial work environment and mental health among travelling salespeople[END_REF][START_REF] Nakanishi | Lifestyle and the development of hypertension: a 3-year follow-up study of middle-aged Japanese male office workers[END_REF][START_REF] Landrigan | Effect of reducing interns' work hours on serious medical errors in Intensive Care Units[END_REF][START_REF] Barger | Extended work shifts and the risk of motor vehicle crashes among interns[END_REF] that limit generalisability of the findings.

Most studies have analysed samples composed of self-employed and salaried workers, but the reasons and the compensations associated with working long hours may differ between these two groups, and therefore the impact of long working hours on health status. It is noteworthy that most epidemiological studies on long workhours and health have been conducted in Japan and have focused on very long working hours but little is known about moderately long workhours. [START_REF] Härmä | Are long workhours a health risk?[END_REF] Some studies that have failed to find an association between poor health and long working hours have considered working hours as a continuous variable and assumed a linear relationship. [START_REF] Park | Regular overtime and cardiovascular functions[END_REF][START_REF] Sorensen | Sex Differences in the Relationship Between Work and Health: The Minnesota Heart Survey[END_REF] However, individuals working few hours are more likely to do so due to a reduction of their usual workhours as a consequence of serious health conditions. Therefore, these studies could have underestimated the association between poor health status and long working hours. It has been pointed out that further studies are needed that take into account some potential confounding or interacting variables such as gender, work characteristics, or domestic work. [START_REF] Harrington | Working long hours and health[END_REF][START_REF] Caruso | Overtime and extended work shifts: Recent findings on illnesses, injuries and health behaviors[END_REF] Most studies on the health impact of long workhours have been carried out among men or have considered sex as an adjusting variable. Nevertheless, there are several reasons why the impact of long workhours can differ by gender. [START_REF] Harrington | Working long hours and health[END_REF] On one hand, physiological changes related to long workhours may not be the same for men and women. [START_REF] Kawakami | Relations of work stress to alcohol use and drinking problems in male and female employees of a computer factory in Japan[END_REF] Moreover, long workhours can contribute to the double burden of full-time and domestic work. Several studies have reported the damaging effects of work conflict and work overload among women who have to balance the responsibilities of both job and family. [START_REF] Artazcoz | Gender inequalities in health among workers: the relation with family demands[END_REF][START_REF] Artazcoz | Combining job and family demands and being healthy: what are the differences between men and women?[END_REF][START_REF] Borrell | Social class and self-perceived health status among men and women: what is the role of work organization, household material standards and household labour[END_REF] In addition, more noticeable effects of long workhours have been observed among women, something often attributed to the additional domestic stressors experienced by women as a result of gender inequalities in the distribution of domestic tasks. [START_REF] Åkerstedt | The future of workhours-the European view[END_REF][START_REF] Ezoe | Behavioural lifestyle and mental health status of Japanese factory workers[END_REF][START_REF] Nylen | Mortality among women and men relative to unemployment, part time work, overtime work and extra work: a study based on data from Swedish twin registry[END_REF] Working long hours depends to a great extent on family responsibilities and constraints imposed by the labour market. Due to both gender segregation within the labour market and family responsibilities, men and women probably work long hours for different reasons; hence the work conditions associated with their schedules also differ.

Consistent with the gender division in the domestic sphere, with women responsible for housework and caring tasks and men usually assuming the breadwinner role, living with children is related to part-time work among women, while, among men, it is likely to be associated with long hours. [START_REF] Milkie | Playing all the roles: gender and the work-family balancing act[END_REF] Regulation on working hours differs across countries. The European Union (EU) work hours directive has included a maximum of 48 hours of work per week. [START_REF] Åkerstedt | The future of workhours-the European view[END_REF] Yet, there are differences among European countries. For example, the Spanish law is more restrictive and establishes a maximum of 40 contractual work hours and a maximum of 80 hours of overtime per person and year. [START_REF] Del | Estatuto de los Trabajadores[END_REF] However, it has been pointed out that overtime regulation, not only in Spain but in the EU, is undermined by illegal practices, as well as the widespread use of special rules and exemptions for certain sectors, types of company and occupational categories. [START_REF] Freyssinet | Overtime in Europe[END_REF] The Japanese government has implemented administrative guidance on overtime, which suggests that all employees should not work 45 hours of overtime per month and that there will be government intervention if overtime exceeds 100 hours per month. [START_REF] Hoshuyama | Overwork and its health effects-current status and future approach regarding Karoshi[END_REF] In the United States there is no regulation regarding limiting working time for adults.

The objectives of this study were (a) to identify family and job characteristics associated with long workhours, (b) to examine the relationship between long workhours and a variety of health outcomes and health-related behaviours, and (c) to examine whether gender differences exist for both objectives.

METHODS

The data have been taken from the 2006 Catalonian Health Survey, a cross-sectional survey based on a representative sample of the non-institutionalised population of Catalonia, a region in the North-east of Spain which has about 7 million inhabitants. The survey included selfreported information on morbidity, health status, health-related behaviours and use of health care services, as well as socio-demographic data. A sample of 18,126 subjects was selected using a multiple stage random sampling strategy with a maximum global error of ±0.7%.

Trained interviewers administered the questionnaires at home in a face-to-face interview.

Only 27% of respondents were replaced as a result of refusal or absence. [START_REF] Mompart | Encuesta de Salud de Catalunya 2006. Un instrumento de planificación sanitaria. [Catalonia Health Survey 2006. A tool for health planning[END_REF] For the purposes of this study a subsample of all salaried workers with a contract aged 16-64 was selected. In order to avoid the effect of extremely long workhours, people working more than 60 hours a week were excluded (2.1% of men and 0.7% of women). The final sample under analysis was composed of 3950 men and 3153 women.

Variables

Working hours were determined using the question: "In the last week (or the last whole week you worked) how many hours did you work?" The response alternatives were <30 hours (part-time job), 30-40 hours (reference category), 41-50 hours, and 51-60 hours a week.

Health and well-being outcomes

Self-perceived health status was elicited by asking the respondents to describe their general health as "excellent", "very good", "good", "fair", or "poor". This is a broad indicator of health related well being [START_REF] Segovia | An empirical analysis of the dimensions of health status measures[END_REF] and has also proved to be a good predictor of mortality, even better than the medical diagnostic. [START_REF] Idler | Self-rated health and mortality: a review of twenty-seven community studies[END_REF] The variable was dichotomised by combining the categories "fair" and "poor" to indicate perceived health as poor health status and the categories "excellent", "very good" and "good" to indicate good health status. Mental health status was measured with the 12-item version of the General Health Questionnaire. We used a two-point scoring method, rating a problem as absent (0) or present (1). The responses were summed, and the participants scoring 3 or more were classified as cases. [START_REF] Goldberg | Manual of the General Health Questionnaire[END_REF] Hypertension was determined by asking people whether they suffered from hypertension or had been diagnosed by a health care professional as having hypertension. Self-reported hypertension has been found to agree with reports in medical records [START_REF] Kehoe | Comparing Self-reported and Physicianreported Medical History[END_REF][START_REF] Ocurra | Agreement between self-report questionnaires and medical record data was substantial for diabetes, hypertension, myocardial infarction and stroke but not for heart failure[END_REF] and with personal blood pressure measurements. [START_REF] Vargas | Validity of self-reported hypertension in the National Health and Nutrition Examination Survey III, 1988-91[END_REF] Job satisfaction was measured with the question "All in all, how satisfied would you say you are with your job?". There were four categories, from "very satisfied" to "very dissatisfied". The responses were dichotomised by combining the categories "very satisfied" and "satisfied" to indicate satisfaction and the categories "dissatisfied" and "very dissatisfied" to indicate job dissatisfaction.

Health-related behaviours

Smoking behaviour was categorized as "no" (current non-smokers and smokers of fewer than one cigarette a day) or "yes". For leisure-time activities, a dichotomous variable was created, comparing no physical activity with slight, moderate, or high intensity of sport activities. The daily number of hours slept was categorized as ≤6 hours and >6 hours.

Employment conditions

Occupational social class, assigned according to the respondent's current occupation, was measured with a widely used Spanish adaptation of the British classification. [START_REF] Domingo-Salvany | Una propuesta de medida de la clase social: Grupo de Trabajo de la Sociedad Española de Epidemiología y de la Sociedad Española de Medicina Familiar y Comunitaria [Proposal for a social class measure: Working Group of the Spanish Society Epidemiology and the Spanish Society of Family and Community Medicine[END_REF] Because of the small number of persons in some categories, the six original social classes were collapsed into the following three broad classes: I and II (more privileged classes), III, and IVA-IVB-V (manual workers). Type of contract had three categories: Permanent, fixed-term temporary contract and non-fixed term temporary contract. Shift type was coded as day, night, shifts and variable depending on the day.

Family and domestic characteristics

Marital status was classified into four categories: married or cohabiting, single, separated or divorced, and widowed. Number of children living at home was coded into three categories: none, one and two or more. Weekly hours of domestic work were recorded as <10 hours, 10-20 hours, and >20 hours.

Data analysis

First, gender differences for all of the dependent and independent variables were tested at the bivariate level using the chi-square test for categorical variables and the t-test for age. Second, factors associated with working 41-50 or 51-60 hours a week as compared with working 30-40 hours, were identified by fitting multiple logistic regression models for the men and women separately and including age, and job and family characteristics. Third, multiple logistic regression models separated by gender and adjusted for age, and job and family characteristics were fitted in order to test the association between long workhours and all of the health indicators.

RESULTS

General description of the population

Table 1 shows a general description of the population. Regarding health outcomes, no gender differences were found for job satisfaction, women were more likely to report poor selfperceived health status and poor mental health status, whereas self-reported hypertension was more frequent among men. Smoking prevalence was higher among men but no gender differences were observed for leisure time physical activity or daily number of hours slept. 10 Women were more likely to work part-time, whilst working 41-50 hours or 51-60 hours was more frequent among men. 30.1% of men reported working 41-50 hours a week and 7.6% 51-60 hours. The corresponding proportions for women were 14.5% and 2.3% respectively.

Conversely, number of hours of domestic work were higher among women. Whereas 27.5% of women worked more than 20 hours a week, the proportion among men was 7.0%.

Factors related to long workhours

Table 2 shows factors associated with working 41-50 hours as compared with working 30-40 hours by gender. In both sexes, long workhours were more frequent among those with variable shifts depending on the day and was negatively associated with age. Additionally, among women, it was positively associated with night shifts and negatively related to nonfixed term temporary contracts and to more than 20 hours of domestic work a week. Whilst among women no association was found between long workhours and family roles, men married or cohabiting (aOR=1.42, 95% CI=1. 13

Association between long workhours and health

Table 4 shows the association between health outcomes and working hours. The relationship of long workhours with health and health related behaviours was much more consistent among men. In males, working 51-60 hours a week was associated with six out of the seven outcomes analysed. Moreover, a gradient from standard working hours to 51-60 hours a week was found for the six outcomes.

DISCUSSION

This study of representative data from an Spanish region adds to the growing body of evidence indicating that long working hours can substantially increase the risk of several poor health outcomes. Unlike other studies, our investigation has the advantage of covering a large variety of jobs, and overcoming many limitations of earlier research, for example by using a large sample and controlling for the potential confounding effect of age and a variety of job and family characteristics as well as by adopting a gender perspective.

The present study produced three main findings. First, factors associated with long workhours differed by gender. Second, among males there was a consistent association of long working hours with six of the seven health indicators analysed. Third, a notable result of our analysis was the detection of a dose-response relationship among men, from an standard number of hours to 51-60 hours a week for these six health indicators.

As has been mentioned before, results of studies about long working hours and health status are contradictory. This is the case for the seven indicators analysed in this study. For example, whereas some authors have found a positive relationship between long working hours and poor general health status, 32 others have not. 5 33 However, whereas some authors have reported a positive association with depression, 5 others have not observed any relationship. [START_REF] Baldwin | Young doctors' health: I. How do working conditions affect attitudes, health and performance?[END_REF] Findings about hypertension are also contradictory. Whereas some studies have reported a positive relationship, 33 35 others have found no association 11 12 and, even, a negative relationship has also been observed. [START_REF] Nakanishi | Long working hours and risk for hypertension in Japanese male white collar workers[END_REF] As in the present study, earlier research has found an association between long working hours and job dissatisfaction. 33 37 Whilst some studies have observed a positive relationship between long working hours and smoking, 33 38 others have not found it. 7 39 40 Although a positive association has been reported between extended hours and lack of physical activity during leisure time, [START_REF] Artazcoz | Gender perspective in the analysis of the relationship between long workhours, health and health-related behavior[END_REF] other studies have not observed any relationship. 7 39 41 Finally, shortage of sleep is the most consistent finding in the relationship between long working hours and health status. 4 33 36 42 Consistently, in our study, working 51-60 hours was associated with sleeping 6 hours or less a day in both sexes.

Therefore, the consistent association of extended workhours with a variety of health indicators among men is the main finding of this study. Gender differences in the association between long workhours and health outcomes is an interesting observation that can provide some clues for understanding the mechanisms that underlie the relationship between long working hours and health.

Whereas among women, working 41-50 hours was only associated with one health outcome, among men it was associated with 3. Moreover, working 51-60 hours was positively related to six out of the seven health outcomes analysed among males but with only two among females.

Additionally, a gradient was found among men. It can be argued that the more consistent association of working 51-60 hours a week with health outcomes among males could be explained by an insufficient statistical power among women due to the low number of females working this schedule. However, when new logistic regression models were fitted with a single category of long workhours, working 41-60 hours a week was associated with all the outcomes except self-perceived health status among men but only with job dissatisfaction among women (results not shown).

It has been suggested that the relationship between workhours and ill health could be mediated by stress in that long hours act both directly as a stressor increasing the demands on those who attempt to maintain performance levels in the face of increasing fatigue and indirectly by increasing the time that a worker is exposed to other sources of workplace stress. 2 43 It has also been suggested that long working hours can be one indicator of a global poor psychosocial work environment among vulnerable workers. [START_REF] Artazcoz | Gender perspective in the analysis of the relationship between long workhours, health and health-related behavior[END_REF] Finally, the importance of choice in determining a person's response to long hours has being also pointed out. 33 37 44 45 Therefore, there are several factors than can mediate in the relationship between long working hours and health status, some of them having a positive effect on health and others being negative. The results of our study among males suggest that there should be a strong and consistent factor that explains such a consistent association between long work hours and health status, that could be marital status. In this study, compared with males working 30-40 hours a week, those working both 41-50 hours and 51-60 hours were consistently more likely to be married or cohabiting and separated or divorced, whereas no association with marital status was found among women. This finding suggests a possible relationship between long working hours and family financial stress among men, since they traditionally assume the role of family breadwinner. The obligatory nature of working long hours due to family financial stress among people who have the breadwinner role could explain the relationship between long working hours and poor health outcomes found in the subsample of males. Pressure to work long hours in order to increase the income and/or acceptance of poor working conditions, one of them being long working hours, due to fear of job loss in a situation of economic vulnerability, can be some of the reasons that explain the consistent pattern of association of long working hours with several health outcomes among men (figure 1). Our interpretation about overtime related to the need of increasing the income among men is supported by a study based on the 5 th Spanish Working Conditions Survey that reported that receiving an economic compensation for overtime was significantly more frequent among men (60.1% versus 34.4%). [START_REF] Artazcoz | El estrés en una sociedad instalada en el cambio. [Stress in a changing society][END_REF] This hypothesis is also supported by the consistent association between working long hours and job dissatisfaction and the gradient found among males, whereas among women the association existed only for those working 41-50 hours. This interpretation about the importance of the mandatory nature of long working hours is also consistent with the study of Van der Hulst et al. [START_REF] Van Der Hulst | Associations between overtime and psychological health in high and low reward jobs[END_REF] that concluded that even a limited number of hours of involuntary overtime is associated with adverse mental health in low reward situations. Nakanishi et al. [START_REF] Nakanishi | Long working hours and risk for hypertension in Japanese male white collar workers[END_REF] reported a negative association between long working hours and hypertension among male white collar workers. In that study, architects or research workers did more overtime than clerks, and being an architect or a research worker (versus being a clerk) was negatively associated with blood pressure. The authors related this finding to the non mandatory nature of long working hours in this highly qualified group. As architects or research workers who work overtime might be especially competitive, or may particularly enjoy their work, they may not feel working long hours as job strain or stress. [START_REF] Trinkoff | Work schedule characteristics and substance use in nurses[END_REF] Our findings are consistent with those of Artazcoz et al. [START_REF] Artazcoz | Gender perspective in the analysis of the relationship between long workhours, health and health-related behavior[END_REF] that observed a positive relationship between long working hours and a variety of health outcomes only among females, among whom working long hours was associated with being separated or divorced, whilst among males there was no relationship with marital status. They are also consistent with a study showing a relationship between financial stress and risk of acute myocardial infarction among men but not among women. [START_REF] Rosengren | Association of psychosocial risk factors with risk of acute myocardial infarction in 11 119 cases and 13 648 controls from 52 countries (the INTERHEART study): case-control study[END_REF] It should be taken into account that between 2002 and 2005, in Spain, financial stress among families has significantly increased. For example, whereas in 2002 the percentage of household units with a ratio between debt and income higher than 3 was 3.4%, in 2005 it was 9.5%. 49 In Spain financial stress is closely related to the high increase in housing prices over the last decade. This situation is likely to be common in other developed countries. According to a study about 17 industrialised economies between 1970 and 2003, most of the countries experienced a house price boom after the mid-1990s. During this period, housing price growth was particularly strong in Ireland, the Netherlands and the United Kingdom followed closely by Australia, Spain and a number of Nordic countries, where the pace of growth was accelerated in more recent years. [START_REF] Tsatsaronis | What drives housing price dynamics: cross-country evidence[END_REF] Additionally, it should be taken into account that Spain has the highest home ownership rate in Europe. Unfortunately, studies about financial stress and health are still scarce.

Self-perceived health status was the only health indicator not related to long working hours either in men or women. It seems that long workhours would be primarily related to psychosocial health conditions rather than with pain or physical limitations which would be likely to prevent them from working long hours. Actually, whereas no differences in the prevalence of long-standing limiting illness by working hours were found among women, among men the prevalence of long-standing limiting illness was 14.8% among those working part-time, 8.1% among those working 30-40 hours a week, and 7,4% among those working 41-50 or 51-60 hours a week.

Limitations

This study can be limited by its cross-sectional design. However, reverse causation, whereby long working hours would not lead to poor health status and health-related behaviours, but rather the opposite, in other words, that people with poor health status and health-related behaviours would be more likely to work more than 40 hours a week, does not seem plausible. Besides data about long-standing limiting illness that support this hypothesis, whereas no differences in the prevalence of sickness leaves longer than 3 months by working hours were found among women (n=99), among men (n=53) the prevalence decreased with increasing working hours (4.5% among males working part-time, 1.4% among those working 30-40 hours, 0.9% among those working 41-50 hours and 0.3% among those working 51-60 hours). Therefore, health problems associated with long working hours in this study are primarily health conditions and behaviours that have often been related to stress or to lack of time for oneself.

It can be argued that there should be differences in the association between long working hours and health status by social class. Yet, multiple logistic regressions models additionally separated for manual and non-manual workers were fitted and the patterns of associations were similar (results not shown). It should be taken into account that between 2001 and 2005, the proportion of Spanish families with a housing debt increased from 21.6% to 26.1%.

However, there was not such increase in households in the lowest two deciles of income.

Moreover, the percentage of families with this kind of debt was higher among families with higher income. 49 These facts could explain the lack of interaction between long working hours and social class.

Although we have hypothesized that gender differences in the relationship between long working hours and poor health outcomes can be related to the mandatory nature of working long hours related to family financial stress among males, and have provided many arguments supporting this hypothesis, no specific questions about these issues were collected in the survey. Further research should be carried out in order to confirm this hypothesis.

Conclusions

As far as we know, this is the first study in reporting such a consistent association between moderately long workhours and a variety of health indicators and health-related behaviours.

Present competition from countries with low wages and low social costs seems at present to influence working hours to start to increase again. [START_REF] Åkerstedt | The future of workhours-the European view[END_REF] However, our findings suggest that even moderately long work hours may act as a risk factor for health mainly when it is involuntary, for example because of family financial stress among breadwinners as seems to be the case in this study. Accordingly, policies most fruitful for improving workers' health should focus on reducing long working hours when it is mandatory and harmful.

What is already known on this subject

• In the last years several studies have found an association between long working hours and different health indicators.

• However, the number of studies concerning the different areas of health is still low and the results are often contradictory. The inconsistent findings can be related to several methodological shortcomings of previous research, including small sample sizes or unique industry specific circumstances. Moreover, most studies have focused on very long working hours but little is known about moderately long workhours.

What this paper adds

• As far as we know, this is the first study based on a large representative sample of the working population that shows such a consistent association between moderately long working hours and a variety of health indicators.

• A notable result of our analysis is the detection of a systematic dose-response relationship between long working hours and health and health-related behaviours among men from an standard number of hours to 51-60 hours a week.

• The consistent association of long working hours with six out of seven health indicators among men could be explained by their role of family breadwinners that in situations of family financial stress can be related to pressure to work long hours in order to increase the income and/or acceptance of poor working conditions, one of them being long working hours, due to fear of job loss.

Figure 1 .

 1 Figure 1. Proposed model for explaining the mechanism of the relationship between long working hours and health in this study.

Table 1 .

 1 General description of the population (in percentages). Catalonia Health Survey, 2006.

	Men	Women	p
	(n=3950)	(n=3153)

Table 2 . Factors associated with working 41-50 hours a week compared with working the standard number of hours (30-40 hours). Adjusted odds ratios (aOR) and 95% confidence intervals (CI). Catalonia Health Survey, 2006.

 2

		Men	Women
		(n=3475)	(n=2573)
	%	aOR (95% CI)	% aOR (95% CI)

Note: Representative sample of salaried workers of Catalonia (Spain) aged 16-64, working up to 60 hours.

Table 3

 3

	shows factors associated with working 51-60 hours as compared with working 30-40
	hours, by gender. In both sexes, an association with variable shifts depending on the day was
	found. Additionally, among men, working 51-60 hours a week was also related to being
	married or cohabiting (aOR=1.55, 95% CI=1.05-2.29) and being separated or divorced

Table 3 . Factors associated with working 51-60 hours a week compared with working the standard number of hours (30-40 hours). Adjusted odds ratios (aOR) and 95% confidence intervals (CI). Catalonia Health Survey, 2006.

 3

		Men	Women
		(n=2584)	(n=2190)
	%	aOR (95% CI)	% aOR (95% CI)

Table 4 . Association between number of working hours, health and health-related behaviours by gender. Adjusted odds ratios (aOR) and 95% confidence intervals (CI). Catalonia Health Survey, 2006.

 4

			Poor self-perceived	Poor mental health status	Self-reported	Job dissatisfaction	Smoking	No leisure-time physical	Daily number of hours
			health status		hypertension			activity	slept <=6
			% aOR (95% CI)	% aOR (95% CI)	% aOR (95% CI)	% aOR (95% CI)	% aOR (95% CI)	% aOR (95% CI)	% aOR (95% CI)
	Men
	Number of hours of
	paid work a week
	•	30-40 hours	9.5 1	4.8 1	11.4 1	1	33.4 1	5.5 1	25.4 1
	•	<30 hours	9.7 1.28 (0.70-2.35)	5.8 1.24 (0.62-2.45)	10.8 1.69 (0.99-2.91)	11.6 1.07 (0.64-1.78)	29.5 0.78 (0.54-1.11)	6.4 1.57 (0.80-3.05)	25.0 1.06 (0.73-1.55)
	•	41-50 hours	8.6 0.96 (0.75-1.24)	5.7 1.24 (0.91-1.71)	12.4 1.19 (0.95-1.50)	15.3 1.52 (1.23-1.87)*** 35.1 1.11 (0.95-1.29)	9.0 1.73 (1.31-2.27)*** 30.6 1.30 (1.11-1.52)**
	•	51-60 hours	13.4 1.43 (0.98-2.10)	8.8 2.06 (1.31-3.24)** 16.1 1.60 (1.12-2.29)*	20.5 2.05 (1.49-2.82)*** 39.6 1.33 (1.03-1.72)*	12.8 2.43 (1.64-3.60)*** 34.1 1.42 (1.09-1.85)**
	Women
	Number of hours of
	paid work a week
	•	30-40 hours	15.0 1	13.4 1	9.3 1	12.8 1	28.8 1	7.3 1	26.6 1
	•	<30 hours	19.7 1.27 (0.97-1.68)	10.3 0.67 (0.48-0.93)*	8.3 0.81 (0.55-1.19)	13.1 0.95 (0.70-1.29)	28.3 0.97 (0.77-1.23)	6.4 0.85 (0.56-1.30)	23.9 0.83 (0.65-1.06)
	•	41-50 hours	14.5 1.02 (0.75-1.39)	13.4 0.99 (0.73-1.35)	6.1 0.66 (0.43-1.03)	17.7 1.40 (1.06-1.85)*	26.7 0.84 (0.66-1.06)	9.6 1.38 (0.96-1.98)	25.7 1.00 (0.78-1.28)
	•	51-60 hours	21.1 1.38 (0.74-2.55)	18.3 1.43 (0.77-2.65)	9.6 1.06 (0.46-2.46)	20.8 1.53 (0.84-2.79)	47.2 2.27 (1.39-3.70)**	9.7 1.53 (0.69-3.39)	42.5 2.21 (1.34-3.63)**

Note: Odds ratios are adjusted for type of contract, shift type, occupational social class, age, marital status, number of children living at home and number of hours of domestic work. Note: Representative sample of salaried workers of Catalonia (Spain) aged 16-64, working up to 60 hours.

Funding: This work was partially supported by the CIBER en Epidemiología y Salud Pública (CIBERESP), Spain

LICENSE FOR PUBLICATION STATEMENT

The Corresponding Author has the right to grant on behalf of all authors and does grant on behalf of all authors, an exclusive licence (or non exclusive for government employees) on a worldwide basis to the BMJ Publishing Group Ltd to permit this article (if accepted) to be published in JECH and any other BMJPGL products and sublicences such use and exploit all subsidiary rights, as set out in our licence (http://jmg.bmj.com/ifora/licence.pdf).


Martinette T Streppel
email: martinette.streppel@wur.nl

Marga C Ocké

Hendriek C Boshuizen

Frans J Kok

Daan Kromhout

Long-term wine consumption is independently of moderate alcohol intake related to cardiovascular mortality and life expectancy. The Zutphen Study

Keywords: wine, alcohol, cardiovascular, mortality, life expectancy Word count: 3, 692; excluding

Background: Light to moderate alcohol intake lowers the risk of cardiovascular mortality, but whether this protective effect can be attributed to a specific type of beverage remains unclear.

Moreover, little is known about the effects of long-term alcohol intake on life expectancy.

Methods:

The impact of long-term alcohol intake and types of alcoholic beverages consumed on cardiovascular mortality and life expectancy at age 50 was investigated in the Zutphen Study, a cohort of 1,373 men born between 1900 and 1920, and examined repeatedly between 1960 and 2000. Hazard ratios for total alcohol intake and alcohol from wine, beer and spirits were obtained from time-dependent Cox regression models. Life expectancy at age 50 was calculated from areas under survival curves.

Results: Long-term light alcohol intake, i.e. <20 grams per day, compared to no alcohol, was strongly and inversely associated with cerebrovascular (HR: 0.43 [0.26-0.70]), total cardiovascular (HR: 0.70 [0.55-0.89]) and all-cause mortality (HR: 0.75 [0.63-0.91]). Independent of total alcohol intake, long-term wine consumption of, on average, less than half a glass per day was strongly and inversely associated with coronary heart disease (HR:0.61 [0.41-0.89]), total cardiovascular (HR: 0.68 [0.53-0.86]) and all-cause mortality (HR: 0.73 [0.62-0.87]).

These results could not be explained by differences in socioeconomic status. Life expectancy was about 5 years longer in men who consumed wine compared to those who did not use alcoholic beverages.

Conclusion:

Long-term light alcohol intake lowered cardiovascular and all-cause mortality risk, and increased life expectancy. Light wine consumption was associated with a 5 years longer life expectancy; however, more studies are needed to verify this result.

Many studies have demonstrated a U-or J-shaped relationship between alcohol intake and allcause mortality. This association can be explained by a lower risk of cardiovascular disease (CVD) mortality in light to moderate drinkers [START_REF] Pearson | Alcohol and heart disease[END_REF][START_REF] Sasaki | Alcohol and its relation to all-cause and cardiovascular mortality[END_REF][START_REF] Sesso | Alcohol intake and cardiovascular morbidity and mortality[END_REF][START_REF] Corrao | A meta-analysis of alcohol consumption and the risk of 15 diseases[END_REF]. The protective effect of light to moderate alcohol intake may be due to an increase in HDL cholesterol and prevention of blood clotting and reduction of platelet aggregation (5;6). Red wine consumption may have an additional health benefit because of its polyphenolic compounds (7;8) that interfere with the initiation, progression and rupture of atherosclerotic plaques [START_REF] Szmitko | Antiatherogenic potential of red wine: clinician update[END_REF], and improve endothelial function (10;11). Although some epidemiological studies showed beneficial effects of wine consumption (12;13), results of several other studies do not show an advantage of one type of alcoholic beverage over another [START_REF] Rimm | Review of moderate alcohol consumption and reduced risk of coronary heart disease: is the effect due to beer, wine, or spirits[END_REF]. Studies have suggested that the beneficial effects of wine consumption compared to other beverages can mainly be attributed to differences in socioeconomic status, dietary and other lifestyle habits (15;16).

In prospective cohort studies in which alcohol intake is only assessed at the baseline examination, consumption patterns are assumed to be relatively constant over the entire study period. However, it is unlikely that exposure measurements in the past accurately reflect longterm alcohol intake since consumption patterns usually change during life. To get correct estimates of long-term effects of alcohol intake, repeated measures are needed. Moreover, the use of repeated measures, especially when using a cumulative average method, reduces withinsubject variation over time and, thereby, misclassification in alcohol intake [START_REF] Hu | Dietary fat and coronary heart disease: a comparison of approaches for adjusting for total energy intake and modeling repeated dietary measurements[END_REF].

In epidemiological studies, hazard ratios are commonly used to express the impact on mortality. Since hazard ratios express effects for an exposed group relative to the effect of the unexposed group, they do not provide information regarding absolute health effects. Such insight can be obtained by the calculation of life expectancies and the number of life-years lost.

Although concepts like life expectancy are more informative and easier to understand, they are not reported frequently.

The objective of the present study is to assess the relationship between long-term intake of alcohol and the types of alcoholic beverages consumed, and cardiovascular and all-cause mortality. To obtain more accurate effect estimates, we used seven repeated measures of the consumption of alcoholic beverages. In addition to hazard ratios, we present our results also in terms of differences in life expectancy.

METHODS

Study population

The Zutphen Study has been carried out since 1960 among middle-aged men in Zutphen, an old industrial town in the eastern part of the Netherlands with about 30,000 inhabitants. In 1960, a random sample was drawn of 1,088 men born between 1900 and 1919 and residing for at least 5 years in Zutphen. Of those men, 878 participated in the Zutphen Study (response rate: 81%).

Examinations were repeated in 1965, 1970, 1985[START_REF] Shaper | Alcohol and mortality: a review of prospective studies[END_REF], 1995and 2000. In 1985, the group of 554 survivors was extended with a new random sample of men of the same age. Of the 1266 men who were invited in 1985, 939 men participated (response rate: 74%). In every examination round, the participants that took part in both the dietary and physical examinations were selected for the present study (1,373 men).

Assessment of alcohol and food consumption

The habitual alcohol consumption was assessed as part of the total diet, using the cross-check dietary history method [START_REF] Burke | The dietary history as a tool in research[END_REF], adapted to the Dutch situation (19;20). This method provides information about the participant's usual food and alcohol consumption pattern, 6 to 12 months preceding the interview. From 1985 onwards, the information about the usual food and alcohol consumption pattern was limited to the month preceding the interview because consumption patterns from 1985 were much more complicated than those in the 1960s.The daily intake of alcohol, energy and other nutrients was calculated using food composition tables close to the year of measurement [START_REF] Stichting | Voedingscentrum (voorheen Voorlichtingsbureau voor de Voeding)[END_REF][START_REF] Beemster | Creation of a database for the calculation of nutrient intake over time[END_REF][START_REF] Streppel | Een voedingsmiddelentabel voor het uitvoeren van trendanalyses in de Zutphen Studie[END_REF]. Alcohol intake was highly reproducible (r=0.8) [START_REF] Bloemberg | The reproducibility of dietary intake data assessed with the cross-check dietary history method[END_REF] and ranking of the participants was considered valid as shown by the strong correlation with HDL cholesterol [START_REF] Kromhout | Total and HDL cholesterol and their correlates in elderly men in Finland, Italy, and The Netherlands[END_REF].

To assess the relationship between different types of alcoholic beverages and mortality, we calculated the alcohol intake from wine, beer or spirits, respectively. Participants were grouped into three categories according to their intake of total alcohol and of alcohol from beer, wine or spirits: 0, >0-20, and >20 g/d. Since studies have suggested that using non-drinkers as a reference group is unsuitable for studying the effects of alcohol on mortality because of the higher background risk among the former drinkers [START_REF] Wannamethee | Lifelong teetotallers, ex-drinkers and drinkers: mortality and the incidence of major coronary heart disease events in middle-aged British men[END_REF][START_REF] Klatsky | Risk of cardiovascular mortality in alcohol drinkers, ex-drinkers and nondrinkers[END_REF][START_REF] Shaper | Alcohol and mortality: a review of prospective studies[END_REF], we created a time-dependent indicator variable for those men who stopped drinking during follow-up.

Assessment of potential confounders

Detailed information on type and amount of smoking was collected using standardized questionnaires. Cigarette, cigar or pipe smokers were divided into categories of never or longterm ex-smokers, i.e. stopped smoking >10 years ago, recent ex-smokers, i.e. stopped smoking <10 years ago, and current smokers. Also, the number of years of cigarette smoking was calculated. During physical examinations men's weight and height were measured and body mass index (BMI) was calculated. Information about the prevalence and history of clinical myocardial infarction (MI), stroke, diabetes mellitus (DM), and cancer was collected throughout the study.

The men were classified into four levels of socioeconomic status (manual workers, non-manual workers, small business owners and professionals) according to occupation at baseline.

Case ascertainment

Participants were followed until death, or censored on June 30th, 2000. Three participants were lost to follow-up during the study and were censored after their last physical examination.

Information about the causes of death was available from the official death certificate, the medical history collected from interviewing physicians or relatives of the dead person and other witnesses, and from abstracts of hospital and other medical records [START_REF] Menotti | Changes in population cholesterol levels and coronary heart disease deaths in seven countries[END_REF].The adjudication of the underlying causes of death were done by one clinical epidemiologist (Dr Alessandro Menotti, Association for Cardiac Research, Rome, Italy) and coded according to the International Classification of Diseases; Eight Revision (codes 410 to 414 for coronary heart disease [CHD], codes 430 to 438 for cerebrovascular diseases and codes 390 to 458 for CVD) [START_REF]International Classification of Diseases[END_REF]. Because the underlying cause of death in elderly people is often difficult to ascertain, we included primary and secondary causes of cardiovascular death.

Statistical analysis

Cox proportional hazard analyses with age as the time variable (31;32) were performed using the PHREG procedure of SAS/STAT software (version 9.1; SAS Institute, Inc, Cary, NC). Time at entry was age on December 31 st in the year preceding the year the men participated in both the dietary and physical examinations for the first time, i.e. the first measurement round; exit time was age at death, age when lost to follow-up, or age when censored, whichever came first. We calculated the cumulative average alcohol intake to better represent long-term intake. With this method, exposure between 1960 and 1965 was calculated from the alcohol intake from the 1960 examination round; exposure between 1965 and 1970 was calculated from the average alcohol intake from the 1960 and 1965 examination rounds, and so on [START_REF] Hu | Dietary fat and coronary heart disease: a comparison of approaches for adjusting for total energy intake and modeling repeated dietary measurements[END_REF]. For those men who were newly included in the study in 1985, information on alcohol intake was missing in the period 1960-1970. To take into account that average alcohol intake was higher in 1985 than in 1960-1970 and that taking cumulative averages excluding earlier intakes in those men who were newly in the study in 1985 would overestimate their intake compared to men included in 1960, multiple imputation [START_REF] Rubin | Multiple Imputation for nonresponse in surveys[END_REF], five times, of alcohol intake and dietary covariates between 1960 and 1970 was carried out with an adapted version of predicted mean matching [START_REF] Lazzeroni | Robustness of multiple imputation techniques to model misspecification[END_REF]. The SAS code that was used for the multiple imputation can be downloaded from www.rivm.nl/sasmacros. Analyses on long-term alcohol intake were performed on five imputed datasets and results were pooled using the MIANALYZE procedure of SAS/STAT software.

The covariates in the multivariable models included an indicator variable for former drinker, energy intake without alcohol (kcal/d), consumption of vegetables (g/d), fruit (g/d) and fish (g/d), intake of saturated and trans fatty acids (g/d), BMI (kg/m2), cigar or pipe smoking (never and long-term ex, recent-ex and current), cigarette smoking duration (divided by 10 years), the daily number of cigarettes smoked (divided by 10), prevalence of MI (yes or no), stroke (yes or no), DM (yes or no), and cancer (yes or no), and indicator variables for baseline socioeconomic status. In additional analyses, the multivariable models for, respectively, alcohol from beer, wine and spirits were additionally adjusted for total alcohol intake to investigate the independent effects of alcohol from one specified alcoholic beverage type. In the multivariable analyses, the cumulative average intake of all dietary covariates was calculated and non-dietary covariates were updated at each measurement round. To test the proportional hazards assumption, a product term between alcohol intake and age was included in the model, and a p-value for interaction <0.10 was considered statistically significant. We determined differences in life expectancy at age 50, i.e. average age at baseline, between men with different levels of cumulative average alcohol intake, by calculating the area under survival curves [START_REF] Rao | Survival methods[END_REF]. To distinguish between the effects of alcohol intake and the effects of alcoholic beverage types, we compared the life expectancies for men who consumed alcohol from wine (>0 gram per day) with those who consumed alcohol from beer and spirits and those who consumed no alcohol from the specified sources, using cumulative average intake at each measurement round. The men were included in the analysis during the period that they met the requirements for the exposure categories concerned. Cox models, with age as the time variable and stratified by categories of amount (0, >0-20, >20 g/d) or source (no alcohol, alcohol from wine, alcohol from beer or spirits) of alcohol intake, were used to obtain the survival curves. The Cox models were adjusted for baseline covariates, i.e. dietary and smoking variables, BMI, prevalence of chronic diseases, i.e. MI, stroke, DM and cancer, and socioeconomic status. Since several participants used more than one type of alcoholic beverage in their usual diet and are, thereby, included in different exposure categories at the same time, the COVSANDWICH (AGGREGATE) statement was added to the PHREG procedure. Areas under the survival curves from the five imputed datasets were pooled [START_REF] Rubin | Multiple Imputation for nonresponse in surveys[END_REF] and ninety-five percent confidence intervals were obtained using the bootstrap method [START_REF] Efron | An introduction to the bootstrap[END_REF].

RESULTS

Population characteristics

During 40 years of follow-up (mean survival age: 77 years) 1,130 of the 1,373 men participating in the present study died (table 1). Of these deaths, 628 were cardiovascular disease (CVD) deaths, 348 were coronary heart disease (CHD) deaths, and 139 were cerebrovascular deaths.

The percentage of alcohol users almost doubled from 45% in 1960 to 86% in 2000 (table 1). Among users, average alcohol consumption increased from 8 g/d in 1960 to 18 g/d among the survivors in 1985, after which it decreased to 14 g/d in 2000 (table 1). The percentage of wine users increased remarkably from 2% in 1960 till about 40% in 2000. This increase was observed in all levels of socioeconomic status. Among users, the average number of glasses consumed varied between a half and 1.5 glasses per day for wine, beer and spirits. With the exception of 1960, alcohol from spirits contributed the most to the total alcohol intake (figure 1). The correlation between alcohol from spirits and total alcohol intake varied between 0.67 and 0.86.

For alcohol intake from wine and beer, the correlations were lower.

Alcohol consumption, alcoholic beverages and mortality

Long-term alcohol intake was significantly and inversely associated with mortality risk (table 2).

Men with less than or equal to 20 grams of long-term, i.e. cumulative average, alcohol intake had a 57% lower cerebrovascular mortality risk, a 30% lower CVD mortality risk, and a 25% lower all-cause mortality risk compared to men with no alcohol intake. The associations for more than 20 grams of long-term alcohol intake per day were weaker than those for less than or equal to 20 grams of long-term alcohol intake per day.

In the next step, the independent effects of long-term alcohol intake from wine, beer and spirits on mortality were estimated. After additional adjustment for total alcohol intake, less than or equal to 20 grams of long-term alcohol intake from wine per day -compared to no alcohol intake from wine-was inversely associated with CHD (HR: 0.61 [95%CI: 0.41 to 0.89), CVD (HR: 0.68 [0.53 to 0.86]) and all-cause mortality risk (HR: 0.73 [0.62 to 0.87]; table 3). In the models for CVD and all-cause mortality, less than or equal to 20 grams of long-term total alcohol intake remained inversely associated with mortality (HR CVD mortality: 0.76 [0.59 to 0.97]; HR all-cause mortality: 0.80 [0.67 to 0.97]). Additional analyses showed that the inverse association between wine consumption and mortality was present in all socioeconomic classes. Among manual workers, the HRs for long-term wine consumption were 0.63 (0.31 to 1.30) for CHD, 0.78 (0.49 to 1.23) for CVD and 0.78 (0.54 to 1.12) for all-cause mortality. Among the professionals, the hazard ratios were comparable.

Long-term consumption of alcohol from beer and spirits was not independently related to mortality (table 3). However, given the strong correlation between alcohol from spirits and total alcohol intake, these findings should be interpreted with caution. Omiting the adjustment for the prevalence of chronic diseases changed our results slightly but the overall conclusions remained the same.

Alcohol consumption, alcoholic beverages and life expectancy

Men with a long-term alcohol intake less than or equal to 20 grams per day (on average 6 g/d) had a 2.3 years (95%CI: 0.5 to 4.2 years) longer life expectancy at age 50 compared to those who consumed no alcohol. For those men who consumed more than 20 grams of alcohol per day (on average 29 g/d), life expectancy was 1.9 years (-1.1 to 4.9 years) longer compared to non-users.

Men who consumed alcohol from wine, on average 2 g/d, over a longer time period had a 2.5 years longer life expectancy at age 50 (-0.3 to 5.3 years) compared to those who consumed alcohol from beer or spirits (on average about 8 g/d; figure 3) and a 4.7 years (1.6 to 7.7 years) longer life expectancy compared to no alcohol users.

DISCUSSION

Long-term light alcohol intake lowered cerebrovascular, total CVD and all-cause mortality risk, and was associated with a longer life expectancy compared to no alcohol intake. Independent of total alcohol intake, wine consumption was strongly and inversely associated with CHD, total CVD and all-cause mortality. For long-term wine consumers, consuming on average less than half a glass of wine per day, life expectancy at age 50 was about 5 years longer compared to no alcohol users.

The major strength of this study was the collection of detailed information on the consumption of different alcoholic beverages at each of seven examination rounds during 40 years of follow-up. This enabled us to study the effects of long-term, i.e. cumulative average, alcohol intake on mortality. The use of cumulative average intakes reduces within-subject variation over time and, thereby, measurement error. The detailed information on potential confounders such as smoking [START_REF] Sulander | Smoking and alcohol consumption among the elderly: trends and associations, 1985-2001[END_REF][START_REF] Thun | Alcohol consumption and mortality among middle-aged and elderly U.S. adults[END_REF][START_REF] Tsugane | Alcohol consumption and all-cause and cancer mortality among middle-aged Japanese men: seven-year follow-up of the JPHC study Cohort I. Japan Public Health Center[END_REF] diet [START_REF] Forsander | Dietary influences on alcohol intake: a review[END_REF], and socioeconomic status [START_REF] Nielsen | Is the relationship between type of alcohol and mortality influenced by socio-economic status?[END_REF] made it possible to study the independent effect of total alcohol intake and alcohol from different types of alcoholic beverages.

The present study also has some weaknesses. First, recent studies have observed that, among men, frequency of alcohol consumption was inversely associated with coronary heart disease risk, independent of the amount of alcohol consumed [START_REF] Mukamal | Roles of drinking pattern and type of alcohol consumed in coronary heart disease in men[END_REF][START_REF] Mukamal | Drinking frequency, mediating biomarkers, and risk of myocardial infarction in women and men[END_REF][START_REF] Tolstrup | Prospective study of alcohol drinking patterns and coronary heart disease in women and men[END_REF]. Since in the present study, information on alcohol consumption was collected as part of the usual diet, no data was available on drinking frequency. Second, average long-term alcohol intake in the present study was relatively low and most participants used more than one type of alcoholic beverage in their usual diet. This may have led to less precise estimations of the effect of different types of alcoholic beverages on mortality. Third, for those men who were newly included in the study in 1985, information on alcohol intake was missing in the period 1960-1970. By multiple imputations of total alcohol intake, different types of alcoholic beverages and other dietary covariates in 1960-1970, we were able to counter an underestimation of cumulative average intake from 1985 onwards for those men who were newly included in the study. We repeated our analysis among the participants who were included in the study from 1960 (n=875) and found similar associations between long-term total alcohol intake and different types of alcoholic beverages, and mortality. Therefore, it is unlikely that the imputation of total alcohol intake, different types of alcoholic beverages and other dietary covariates among those men who were newly included in the study from 1985 biased our results.

Our results confirm the inverse association between moderate alcohol intake, CVD and all-cause mortality risk observed in other studies (38;39;45-53). In contrast to these and other studies (38;39;45;53-56), the highest exposure level was not associated with an increased mortality risk. However, average alcohol intake in the highest exposure level was relatively low (29 g/d) in the Zutphen Study, which may explain the lack of a positive association between mortality and a higher intake level. In their meta-analysis, Corrao et al. estimated that the risk of CHD mortality is lowest at 16 grams per day with a corresponding hazard ratio of 0.84 [START_REF] Corrao | Alcohol and coronary heart disease: a meta-analysis[END_REF]. In the present study, the hazard ratios for CHD mortality were comparable but not statistically significant (table 2).

Smoking might confound the association between alcohol intake and mortality. Previous results from the Zutphen Study indicated that the number of cigarettes smoked as well as the duration of cigarette smoking are, independently of each other, associated with mortality [START_REF] Streppel | Mortality and life expectancy in relation to long-term cigarette, cigar and pipe smoking: the Zutphen Study[END_REF]. In our multivariable analyses we adjusted for these aspects of smoking. So, it is not likely that the association between alcohol intake and mortality is explained by confounding due to smoking.

In the present study, wine consumption was associated with a lower mortality risk, independent of total alcohol intake. Some studies did not demonstrate a favourable effect of one specific type of alcoholic beverage over another (14;42), while others found an inverse and independent association between wine consumption and mortality (13;59-61). In the present study, 70% of all wine consumed was red wine. This suggests that the cardioprotective effect of wine could be due to a protective effect of polyphenolic compounds in red wine, but other explanations can not be ruled out.

Socioeconomic status might confound the association between wine consumption and mortality. However, in our multivariable analyses we adjusted for socioeconomic status, based on occupation at baseline. At the start of the present study, the men were already in a later phase in their careers and baseline socioeconomic status was considered to be a good indicator during the follow-up period. Furthermore, the increase in the percentage of wine users during follow-up was observed in all levels of socioeconomic status, and additional stratified analyses showed that the inverse association between wine consumption and mortality was present in all socioeconomic classes. These results suggest that the association between wine consumption and mortality can not be explained by confounding due to socioeconomic status.

Long-term wine consumers had about 5 years longer life expectancy at age 50 compared to no alcohol users. Of these 5 years, about 2 years can be attributed to an effect of alcohol intake and is in accordance with the inverse association between long-term alcohol intake and all-cause mortality found in the present study. The remainder 3 years can be attributed to an effect of wine consumption. However, given the wide confidence interval, the effect of wine as such may be overestimated. To our knowledge, we are the first who studied the effects of absolute alcohol intake and type of alcoholic beverage on life expectancy and more studies are needed to verify our results.

In conclusion, long-term light alcohol intake is associated with a lower risk of cardiovascular and all-cause mortality risk, and a longer life expectancy. The inverse associations between wine consumption and mortality remained after adjustment for total alcohol intake.

Wine consumers had a 5 years longer life expectancy compared to no-alcohol consumers; however, more studies are needed to draw conclusions on the strength of the association between wine consumption and mortality. *Crude HR, hazard ratio CI, confidence interval † Hazard ratios are adjusted for former drinking, energy intake without alcohol, the number of cigarettes smoked, cigarette smoking duration, cigar or pipe smoking, intake of vegetables, fruit, fish, saturated and trans fatty acids, body mass index, prevalence of myocardial infarction, stroke, diabetes mellitus and cancer, and baseline socioeconomic status ‡ Hazard ratios are adjusted for former drinking, energy intake without alcohol, the number of cigarettes smoked, cigarette smoking duration, cigar or pipe smoking, intake of vegetables, fruit, fish, saturated and trans fatty acids, body mass index, prevalence of myocardial infarction, stroke, diabetes mellitus and cancer, baseline socioeconomic status, and total alcohol intake § Because of missing data, the number of events may be smaller than the number mentioned in table 1 ¶ NI, because of the small number of men with >20 g of long-term alcohol intake from wine the calculated hazard ratios are not informative.

FIGURE 2

Survival curves for men with a long-term consumption of alcohol from wine, beer or spirits, and no alcohol consumers within the Zutphen Study, adjusted for baseline energy intake without energy from alcohol, the number of cigarettes smoked, cigar or pipe smoking, intake of vegetables, fruit, fish, saturated and trans fatty acids, body mass index, prevalence of myocardial infarction, stroke, cancer and diabetes mellitus, and socioeconomic status.

  Baseline data were collected in 1960 before the Helsinki Declaration was developed and oral informed consent was obtained in view of follow-up data. In 1985 and 1990, the study was approved by the Medical Ethics Committee of the University of Leiden, The Netherlands, and in 1995 and 2000, by the Medical Ethics Committee of the Netherlands Organisation for Applied Scientific Research (TNO).

FIGURE 1

 1 FIGURE 1The contribution of alcohol from beer, wine and spirits to total alcohol intake within the Zutphen Study during 40 years of follow-up.

TABLE 1 . Characteristics of men participating in the Zutphen Study by year of measurement*

 1

	Cohort	1960	1965	1970	1985	1990	1995	2000

TABLE 3 . Long-term consumption of alcohol from beer, wine or spirits in relation to cardiovascular and all-cause mortality within the Zutphen Study Long-term intake (cumulative average, time-dependent)

 3

		Alcohol	Amount	Crude HR	Adjusted HR	Adjusted HR
		source		(95% CI)*	(95% CI) † §	(95% CI) ‡ §
	Coronary	Wine	>0 to 20 g/d 0.59 (0.42; 0.83) 0.60 (0.41; 0.87)	0.61 (0.41; 0.89)
	heart disease		>20 g/d	NI ¶	NI	NI
		Beer	>0 to 20 g/d 0.86 (0.68; 1.09) 0.79 (0.62; 1.02)	0.82 (0.60; 1.12)
			>20 g/d	1.13 (0.41; 3.08) 1.02 (0.35; 2.93)	1.10 (0.36; 3.39)
		Spirits	>0 to 20 g/d 0.93 (0.70; 1.23) 0.85 (0.63; 1.15)	0.92 (0.63; 1.34)
			>20 g/d	0.86 (0.40; 1.84) 0.89 (0.42; 1.86)	1.01 (0.35; 2.97)
	Cerebro-	Wine	>0 to 20 g/d 0.67 (0.44; 1.01) 0.82 (0.53; 1.26)	0.92 (0.58; 1.46)
	vascular		>20 g/d	NI	NI	NI
		Beer	>0 to 20 g/d 0.64 (0.45; 0.93) 0.62 (0.42; 0.92)	0.81 (0.48; 1.35)
			>20 g/d	0.68 (0.09; 5.01) 0.78 (0.10; 6.26)	0.78 (0.09; 6.73)
		Spirits	>0 to 20 g/d 0.76 (0.51; 1.13) 0.79 (0.52; 1.20)	1.44 (0.72; 2.86)
			>20 g/d	0.62 (0.19; 1.97) 0.70 (0.21; 2.34)	0.93 (0.20; 4.32)
	Total cardio-	Wine	>0 to 20 g/d 0.63 (0.51; 0.78) 0.66 (0.52; 0.84)	0.68 (0.53; 0.86)
	vascular		>20 g/d	1.37 (0.19; 9.78) 2.45 (0.33; 18.1)	2.20 (0.30; 16.4)
		Beer	>0 to 20 g/d 0.84 (0.70; 1.00) 0.82 (0.69; 0.99)	0.91 (0.72; 1.14)
			>20 g/d	1.30 (0.62; 2.74) 1.29 (0.58; 2.84)	1.26 (0.55; 2.88)
		Spirits	>0 to 20 g/d 0.85 (0.69; 1.04) 0.82 (0.66; 1.03)	0.93 (0.70; 1.24)
			>20 g/d	0.84 (0.50; 1.41) 0.91 (0.54; 1.55)	0.88 (0.47; 1.64)
	All-cause	Wine	>0 to 20 g/d 0.68 (0.58; 0.78) 0.72 (0.61; 0.85)	0.73 (0.62; 0.87)
			>20 g/d	0.79 (0.11; 5.59) 1.28 (0.18; 9.28)	1.21 (0.17; 8.82)
		Beer	>0 to 20 g/d 0.91 (0.80; 1.05) 0.89 (0.78; 1.02)	0.98 (0.83; 1.17)
			>20 g/d	1.41 (0.84; 2.36) 1.29 (0.76; 2.19)	1.37 (0.74; 2.53)
		Spirits	>0 to 20 g/d 0.86 (0.75; 1.00) 0.87 (0.74; 1.01)	0.97 (0.80; 1.18)
			>20 g/d	1.08 (0.76; 1.53) 1.02 (0.67; 1.55)	1.09 (0.69; 1.73)

*Numbers represent means ± standard deviation, unless indicated otherwise †In every measurement round, the participants that took part in both medical and dietary examinations were selected for the analyses ‡Age is defined as age on December 31st in the year preceding the examination §Never and long-term ex-smokers are defined as men who never smoked or stopped smoking >10 years ago; recent ex-smokers are defined as men who stopped smoking <10 years ago ¶Average alcohol intake was calculated among alcohol users.

Acknowledgements

This work was partly supported by a grant from the former Inspectorate for Health Protection and Veterinary Public Health, at present integrated in the Food and Consumer Product Safety Authority, The Netherlands.

Publication statement

The Corresponding Author has the right to grant on behalf of all authors and does grant on behalf of all authors, an exclusive licence (or non exclusive for government employees) on a worldwide basis to the BMJ Publishing Group Ltd to permit this article (if accepted) to be published in JECH and any other BMJPGL products and sublicences such use and exploit all subsidiary rights, as set out in our licence (http://jmg.bmj.com/ifora/licence.pdf). *Crude HR, hazard ratio CI, confidence interval † Hazard ratios are adjusted for former drinking, energy intake without alcohol, the number of cigarettes smoked, cigarette smoking duration, cigar or pipe smoking, intake of vegetables, fruit, fish, saturated fat and trans fatty acids, body mass index, prevalence of myocardial infarction, stroke, diabetes mellitus and cancer, and baseline socioeconomic status. ‡ Because of missing data in the covariates, the number of events is less than the number mentioned in table 1.

What is already known on this subject: Light to moderate alcohol intake may lower all-cause mortality risk due to a lower cardiovascular mortality risk.

What does this study add?:

The findings from this study suggest that light wine consumption lowers (cardiovascular) mortality risk, independently of total alcohol intake, and may increase life expectancy at age 50.


Miguel Angel
email: fmiguelangel@isciii.es

Luque Fernandez

Aurora Bueno Cavanillas

Michèle Dramaix-Wilmet

Fernando Simón Soria

Juan De Mata

Dionisio Donado Campos

Herrera Guibert

Miguel Ángel

Luque Fernández

Aurora Bueno Cavanillas

Dionisio Herrera

Increase in maternal mortality associated with change in the reproductive pattern in SPAIN: 1996-2005

Keywords: Maternal age, Maternal Mortality, Trends, Reproductive Health, Epidemiology

INTRODUCTION

In 2006, with a mean of 1.3 children per woman at reproductive age, Spain ranked among the group of countries with the lowest total fertility rates in the world, only ahead of the Ukraine and Greece (among others) with 1.1 and 1.2 children per woman respectively. In the last twenty years, despite the low fertility, the number of pregnancies among women aged over 35 years has been rising progressively, accounting for 21.2% of births in 2006. [START_REF] Fernández | Trends in the risk of late fetal mortality, prematurity and low birth weight associated with advanced maternal age in Spain [1996-2005[END_REF] This important increase in fertility among women aged over 35 years has been accompanied by a higher feto-neonatal morbidity and mortality, becoming extremely marked as from age 40 years onwards. [START_REF] Fernández | Trends in the risk of late fetal mortality, prematurity and low birth weight associated with advanced maternal age in Spain [1996-2005[END_REF][START_REF] Nabukera | First-time births among women 30 years and older in the United States: patterns and risk of adverse outcomes[END_REF][START_REF] Jacobsson | Advanced maternal age and adverse perinatal outcome[END_REF] Similarly, the delay in maternity and the progressive rise in maternal age at date of birth have also resulted in higher female morbidity and mortality. Advanced maternal age has been associated with a higher risk of death [START_REF] Seoud | Impact of advanced maternal age on pregnancy outcome[END_REF][START_REF] Diejomaoh | The reproductive performance of women at 40 years and over[END_REF] and an increased risk of delivery by caesarean section during the birth process. [START_REF] Martínez-Frías | Evolución secular y por autonomías de la frecuencia de tratamientos de fertilidad, partos múltiples y cesáreas en España[END_REF][START_REF] Heffner | Impact of labor induction, gestational age, and maternal age on cesarean delivery rates[END_REF] Maternal mortality is regarded as a preventable cause of death, strongly related to the quality of the healthcare system, and economic and social factors. [START_REF] Bouvier-Colle | Mise au point sur la mortalité maternelle en France: fréquence, tendances et causes[END_REF][START_REF] Sheiner | Infertility treatment is an independent risk factor for cesarean section among nulliparous women aged 40 and above[END_REF][START_REF] Bouvier-Colle | Les morts maternelles en France[END_REF] The quality of healthcare and maternal care furnished to pregnant women is an element that may account for the differences between rates. [START_REF]Report on Confidential Enquiries into maternal deaths in the United Kingdom 1991-1993[END_REF][START_REF] Schuitemaker | Confidential enquiry into maternal deaths in The Netherlands 1983-1992[END_REF] In Spain, a study conducted into the maternal mortality trend for the period 1980-1992 reported a certain stabilisation in the maternal mortality ratio, even so the authors of this study forecast an increase in maternal mortality for the year 2000, associated with advanced maternal age and delay in maternity. [START_REF] Valero | Maternal mortality in Spain, 1980-1992. Relationship with birth distributions according to the mother's age][END_REF] Although this increase has also been forecast for France and England for 2005, [START_REF] Salanave | The likely increase in maternal mortality rates in the United Kingdom and in France until 2005[END_REF] there are no comparative analysis data available for the prevalence of pregnancies among women aged of the pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes" [START_REF]International Classification of Diseases. 10 th Revision[END_REF]. The maternal mortality ratio was calculated as the rate between maternal deaths observed for any given year and total live births for this same year expressed per 100,000 newborns; it thus represents the risk of maternal death with respect to the number of newborns. The number of live births used in the denominator is an approximation of the population of pregnant women who are at risk of a maternal death. [START_REF] Who | Maternal mortality in 2005. Estimates developed by WHO, UNICEF and UNFPA[END_REF] For the individual description of socio-demographic factors related to maternal deaths, the following variables were used: age; province of birth and death registration; and finally, the ICD-10 diagnostic code of cause of death, obtained from the register of deaths statistics broken down by cause of death.

Statistical analysis: The median, the interquartile range, and the 5 th and 95 th percentiles were used for the description of maternal deaths. Considering maternal death as a rare event, and assuming that the maternal mortality ratio follows a Poisson distribution, maternal mortality ratios were calculated together with their respective 95% confidence intervals.

The trend in observed vis-à-vis expected deaths for each year of study was represented graphically in accordance with a Poisson distribution. The trend in mortality ratios was also represented graphically. A χ 2 test for trend was applied to the ratios and, using linear adjustment by the least squares method, a trend line was added to the figure, accompanied by the formula of the equation of the straight line and the coefficient of determination (R 2 ).

To confirm the trend in the series, standardised mortality ratios were calculated using the indirect method and taking 1996 as reference. Subsequently, in view of the small number of events that occur annually, the mortality ratios of the two quinquennia of the series were calculated in order to give more consistency to the analysis of the series. Using indirect standardisation and taking the five-year period from 1996 to 2000 as reference, the standardised mortality ratio for the five-year period 2001-2005 was then calculated. [START_REF]INphoRM 6:Standardisation[END_REF] To analyse risk of death in terms of maternal age, the age-related mortality rates categorised in three groups (≤ 34, 35 to 44, and ≥ 45 years) were graphically represented (for the whole study period). A χ 2 test for trend was applied to the ratios, and, lastly, a model with an exponential fit was depicted in the figure with its respective equation and coefficient of determination.

An exact Poisson regression was used to estimate the maternal age-related risk of death, adjusted for the study period. The explanatory model used was as follows:

MMR = β 0 + β 1 *Period (continuous variable) + β 2 *Age (categorical variable)
The statistical test of deviance was used to estimate goodness-of-fit, and an analysis of standardised Pearson residuals was performed.

RESULTS

The prevalence of live births among women aged 35 years and over in Spain was 15% higher than the European Union (EU15), over the five-year period 2000-2005. Along with Ireland and Italy, Spain registered the highest prevalence; Portugal was the country with the lowest prevalence (Table1) During the period 1996-2005, there were 148 maternal deaths in Spain. The descriptive analysis revealed an annual median of 15 deaths for the study period, with an interquartile range of 7, and a 5 th and 95 th percentile of 8 and 21 deaths respectively. The maternal mortality ratio for the period was 3.6 (95% CI:

3.1-4.3) women per 100,000 live births. Taking 1996 as reference, the standardised mortality ratio displayed an upward trend at the limit of significance (p= 0.079). Maternal deaths increased by 55% in the period 2001-2005 compared with 1996-2000 (Table 2). The maternal mortality ratio for the study period reflected linear growth (p= 0.012) (Figure 1) and indicated two years with highest mortality. The maternal mortality represented a 50% increase mortality in 2003 and 2004, taking as reference 1996 (Table 2).

Across the entire study period, the curve that best explained the trend in maternal age-related mortality ratios was that which depicted exponential growth (Figure 2).

Adjusted for the study period, the maternal age group ranging from 35 to 44 years displayed a 2.9-fold higher risk of death compared to the 34-and-under age group. This higher risk rose to as much as 89.2-fold in the case of the 45and-over age group (Table 3).

, Valladolid (1), Zaragoza (1) (Figure 3). The groups O10-O16 and O85-O92 are presenting a 48.7% of all deaths of the biennium 2003, 2004.

In the first group, pre-eclampsia/eclampsia accounts for 90% (9 deaths) of the deaths and embolism (amniotic fluid, 4 deaths, the blood clot in obstetrics, 3 deaths and other obstetric embolism, 1 death) accounts for 80% of deaths in the second group.

CONCLUSIONS:

From 1930 up to the 1980s, the maternal mortality ratio registered a clear decline in most European countries, with it then remaining stable in the following years. [START_REF] Schuitemaker | Maternal mortality and its prevention[END_REF][START_REF] Atrash | Maternal mortality in developed countries: not just a concern of the past[END_REF] In the 1990s, different authors forecast a rise in the maternal mortality ratio by the beginning of the 21 st century, specifically in Spain, France and the United Kingdom. [START_REF] Valero | Maternal mortality in Spain, 1980-1992. Relationship with birth distributions according to the mother's age][END_REF][START_REF] Salanave | The likely increase in maternal mortality rates in the United Kingdom and in France until 2005[END_REF] In line with these forecasts, the results of this study confirm a change in the maternal mortality trend in Spain over the decade 1996-2005.

In Spain, the risk of maternal mortality grew exponentially with mothers' age over the decade 1996-2005. This is the first time that a study has drawn attention to the high percentage of maternal deaths among the foreign population in Spain (32% of total deaths during the two-year period from 2003 to 2004). In this respect, other studies have identified women at advanced reproductive age and immigrants from developing countries as risk groups for maternal mortality. [START_REF] Schuitemaker | Confidential enquiry into maternal deaths in The Netherlands 1983-1992[END_REF][START_REF] Salanave | The likely increase in maternal mortality rates in the United Kingdom and in France until 2005[END_REF] However, the data yielded by our study do not enable us to specify what percentage of the figure of 32% recorded for deaths among foreign mothers is attributable to mothers from developing countries. In this connection, a study on maternal mortality in Europe highlights the fact that there is a wide disparity between migrants from developing countries and the native population in terms of access to health. Communication problems between health professionals and immigrant patients have been postulated as being a key factor underlying this problem. [START_REF] Schuitemaker | Maternal mortality in Europe; present and future[END_REF] According to Eurostat data, the mean age of first pregnancy in most European countries is rising. [START_REF]Statistical Office of the European Communities[END_REF] The determinants of this process can be explained by the social, economic and cultural changes that took place in western societies in the last third of the 20 th century. Specifically, here in Spain, the lack of conciliation between professional and family life, absence during years of maternity of protective policies, and the progressive medicalisation of pregnancy and birth have been suggested as determinants of the increase in the mean age of mothers at first pregnancy. [START_REF] Maroto-Navarro | The challenge of maternity in Spain: social and health difficulties[END_REF] Furthermore, the development of assisted reproduction techniques, different prenatal diagnostic tests, legal termination of pregnancy after prenatal diagnosis of congenital defects, [START_REF] Martínez-Frías | Frecuencia basal de defectos congénitos en España y su evolución en el tiempo: utilidad y significado de las distintas cifras de frecuencia[END_REF] and delivery by caesarean section with enhanced safety for mother and foetus, have brought greater guarantees of safety for couples who can now delay maternity with a certain degree of tranquillity. [START_REF] Sachs | The risk of lowering the cesarean-delivery rate[END_REF] This would account for the fact that Spain and Italy, with some of the lowest total fertility rates in Europe (a mean of 1.2 to 1.3 children per woman at reproductive age), [START_REF]Statistical Office of the European Communities[END_REF] are the two countries which have the highest number of assisted reproduction clinics (115 and 182 respectively) and register the highest prevalence of births among women aged 35 years and over in Europe. [START_REF] Andersen | Assisted reproductive technology in Europe, 2001. Results generated from European registers by ESHRE[END_REF] This change in the fertility pattern has led some authors to forecast future rises in maternal mortality. [START_REF] Salanave | The likely increase in maternal mortality rates in the United Kingdom and in France until 2005[END_REF][START_REF] Atrash | Maternal mortality in developed countries: not just a concern of the past[END_REF] The individual descriptive analysis of maternal deaths which occurred during the two-year period with highest mortality (2003)(2004), has enabled a cluster of deaths to be located in one Spanish province. Confidential surveys conducted in France, United Kingdom and Holland in the 1990s estimated that the proportion of maternal deaths which did not benefit from an optimal level of care accounted for 50% to 80% of the cases reviewed. [START_REF] Bouvier-Colle | Maternal deaths and substandard care: the results of a confidential survey in France. Medical Experts Committee[END_REF][START_REF] Benbow | Reducing maternal mortality: reaudit of recommendations in reports of confidential inquiries into maternal deaths[END_REF][START_REF] Wildman | Maternal mortality as an indicator of obstetric care in Europe[END_REF] Accordingly, this is a factor that might well explain the difference in maternal mortality between regions.

This is why confidential investigations into maternal death are indispensable for furnishing a more reliable image of what is in fact happening. Such research requires every effort to be made to gather comprehensive data on all the possible variables underlying the event. Individualised nation-wide studies on maternal deaths started being conducted in the United Kingdom in 1952 and in

The Netherlands shortly thereafter. [START_REF] Schuitemaker | Confidential enquiry into maternal deaths in The Netherlands 1983-1992[END_REF][START_REF]Report on Confidential Enquiries into Maternal Deaths in the United Kingdom 1994-1996[END_REF] Insofar as the limitations of this study are concerned, it must be stressed that, when one talks of risk of maternal mortality associated with age, this is not interpretable at an individual level: to do so, would be to fall foul of an ecological fallacy. Different authors have highlighted problems of under-registration and under-reporting of maternal deaths in different European countries and Spain, [START_REF] De | Mortalidad materna en España en el período 1995-1997: resultados de una encuesta hospitalaria[END_REF] and so the results of our study could be underestimated. One must be prudent when it comes to interpreting the results, in view of the fact that probability distributions for infrequent events increase the risk of type I error and, at times, yield p-values that are difficult to interpret. To solve this problem when analysing the data, we therefore endeavoured to lend the results greater consistency by adding maternal deaths for periods of five years in order to perform five-yearly comparisons. Prudence is also called for when it comes to interpreting the mortality cluster detected. For a correct interpretation, one would have to access to a longer time series. Similarly, it is highly likely that most of the clusters of adverse results in reproductive health are random events: only a very small proportion are caused by environmental agents, which could be identified by exhaustive epidemiological research. [START_REF]Guidelines for investigating clusters of health events[END_REF][START_REF] Niyonsenga | A method for the follow-up of clusters of adverse reproductive outcomes[END_REF] The change in the maternal mortality pattern detected marked by a rising trend and an increased risk at advanced maternal ages, the detection of a cluster with geographical excess mortality, plus the high prevalence of pregnancies among women aged 35 years and over in Spain versus other European countries, justify the need for more intense and detailed epidemiological surveillance of a preventable phenomenon. It would be desirable to conduct an assessment of under-registration and under-reporting, implement active surveillance to put a halt to geographical clusters, use qualitative surveys for analysis of the socioeconomic and health-care circumstances surrounding deaths, and perform comparative quantitative analyses in the European sphere, both national and regional. These measures would be invaluable for in-depth understanding and characterisation of a preventable phenomenon such as maternal death.

What is already known on this subject?

The delay in maternity and the progressive rise in maternal age at date of birth have also resulted in higher female morbidity and mortality. Maternal mortality is regarded as a preventable cause of death, strongly related to the quality of the healthcare system, and economic and social factors.

Different studies forecast an increase in maternal mortality, associated with advanced maternal age and delay in maternity in the next years. The maternal mortality trend in Spain needs to be re-assessed, as does the impact of advanced age on this trend.

What does this study add?

This study adds a change in the maternal mortality pattern in Spain marked by a rising trend and an increased risk at advanced maternal ages, the detection of a cluster with geographical excess mortality, plus the high prevalence of Implement active surveillance to put a halt to geographical clusters, use qualitative surveys for analysis of the socio-economic and health-care circumstances surrounding deaths, and perform comparative quantitative analyses in the European sphere, both national and regional. These measures would be invaluable for in-depth understanding and characterisation of a preventable phenomenon such as maternal death.

  35 years and over in Spain versus Europe, and the maternal mortality trend in Spain needs to be re-assessed, as does the impact of advanced age on this trend. Accordingly, this study sought to: compare the prevalence of live births among mothers aged 35 years and over in Spain versus Europe during the last five years of the study period, 2000-2005; analyse the age-related trend in the maternal mortality ratio among mothers in Spain for the decade, 1996-2005; and describe the causes of death and associated socio-demographic factors for the years with highest mortality. METHODS An ecological study on trends, using aggregate data for the maternal mortality trend during the period 1996-2005; and cross sectional using individual data for describe ascertaining causes of maternal death and associated sociodemographic factors, during 2003-2004. Data source: Data on Europe were drawn from the European Statistics Office (Eurostat). Eurostat calculates the European aggregates on the basis of the data collected from the National Statistical Offices.[16] Data on Spain were drawn from the National Statistics Institute, we used the movement of natural persons (MNP) and death statistics broken down by cause of death.[17] Description of variables: The total births by mother's age in Europe, for 2000 to 2005 obtained from Eurostat, were used to describe the prevalence of births among women aged 35 years and over for 15 European Countries. The variables used to describe the maternal mortality trend in Spain were the total number of births and maternal deaths by mother's age at the date of birth for each year of the study period, obtained from the MNP. The definition of maternal mortality used was that proposed by the International Classification of Diseases, 10th Revision (ICD-10), i.e., "the death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the duration and site

Finally, after identifying

  the years with highest mortality, the socio-demographic factors related to maternal deaths were individually described. The statistical software programme used was Stata v.10 (StataCorp. College Station, TX, USA).

[ 1 . 5 - 6 . 1 ]

 1561 ). The number of maternal deaths by provinces in Spain for the period 2003-2004 were: Alicante (3), Almeria (1), Asturias (3), Badajoz (1), Balearic Isles (1), Barcelona (5), Cadiz (1), Ceuta (1), Jaén (2), Las Palmas (1), Lleida (1), Madrid (5), Málaga (8), Murcia (1), Santa Cruz de Tenerife (2), Seville (1), Pontevedra

  pregnancies among women aged 35 years and over in Spain versus other European countries. This pattern change poses the need of intensifying maternal mortality surveillance in Spain by collecting the necessary set of variables that allow investigation of the causes and determinant factors underlying deaths.

Figures legend: Figure 1 .

 1 Figures legend: Figure 1.Annual trend in the absolute number of deaths and maternal mortality ratios for the period 1996-2005 (n: 148).

Figure 2 .

 2 Figure 2.Age-related maternal mortality ratio for the period 1996-2005 (n: 148).

Figure 3 . 2

 32 Figure 3. Maternal Mortality by province of death in Spain (n: 41): 2003-2004.

Table 1 . Prevalence of live births among women aged 35 years and over for 15 European Countries (UE15): 2000-2005. Countries (EU15) LBMA ≥ 35 years (n) Total Live Births (N) Prevalence % (P) Difference in P PR *

 1

	Italy	750,190	3,176,749	23.6	4.6	1.24**
	Ireland	83,441	355,940	23.4	4.4	1.23**
	Spain	566,354	2,585,701	21.9	2.9	1.15**
	Sweden	110,412	579,153	19.1	0.1	1.01**
	Netherlands	228,506	1,193,527	19.1	0.1	1.01**
	Luxembourg	6,103	32,616	18.7	[-0.3]	0.98**
	Germany	797,526	4,318,210	18.5	[-0.5]	0.97**
	Finland	62,703	340,619	18.4	[-0.6]	0.97**
	United Kingdom	757,974	4,150,737	18.3	[-0.7]	0.97**
	Austria	72,212	404,309	17.8	[-1.2]	0.94**
	France	786,333	4,807,827	16.3	[-2.7]	0.86**
	Greece	101,912	626,738	16.2	[-2.8]	0.85**
	Denmark	62,301	390,264	16.0	[-3.0]	0.84**
	Portugal	100,083	678,359	14.8	[-4.2]	0.78**
	Belgium***	-	-	-	-	-
	Total (EU15) (Ref.)	4,486,050	23,640,749	19.0	Ref.	Ref.

Live Births with maternal age ≥ 35 years old (LBMA), Reference (Ref.) *Prevalence Ratio ** P-value <0.01, *** No data Data Source: Eurostat. In-house.

Table 2 . Maternal Mortality Ratios and Standardized Mortality Ratios in Spain (n: 148 maternal deaths; n: 4,062,685 live births): 1996-2005.

 2

				MMR
	Years/Period	OMD	NLB	(95% CI)	EMD	SMR	P-value
	1996	11	362,626	3.0 (1.7-5.5)	Ref.	Ref.	0.079*
	1997	8	369,035	2.2 (1.1-4.3)	11	0.7 (0.5-1.1)
	1998	10	365,193	2.7 (1.5-5.1)	11	0.9 (0.6-1.3)
	1999	15	380,130	4.0 (2.4-6.5)	11	1.3 (0.9-1.7)
	2000	14	397,632	3.5 (2.1-5.9)	12	1.2 (0.9-1.6)
	2001	17	406,380	4.2 (2.6-6.7)	12	1.4 (0.9-1.8)
	2002	14	418,846	3.3 (2.0-5.6)	13	1.1 (0.8-1.5)
	2003	20	441,881	4.5 (2.9-7.0)	13	1.5 (1.2-1.9)
	2004	21	454,591	4.6 (3.0-7.1)	14	1.5 (1.2-2.0)
	2005	18	466,371	3.9 (2.4-6.1)	14	1.3 (0.9-1.7)
	1996 to 2000	58	1,874,616	3.1 (2.4-4.0)	Ref.	Ref.	0.089**
	2001 to 2005	90	2,188,069	4.1 (3.3-5.1)	77	1.2 (0.9-1.4)

Observed Maternal deaths (OMD), Number of live births (NLB), Maternal Mortality Ratio (MMR), Expected Maternal Death (EMD), , Standardised Mortality Ratio (SMR). * Trend χ2 ** χ2 for unequal rates Data source: INE, In-house

Table 3 . Maternal mortality ratios according to maternal age and study period (n: 148 maternal deaths): 1996-2005.

 3 Goodness-of-fit χ 2 : 26.7, p= 0.421 Age-related socio-demographic characteristics, nationality (Spanish versus foreign), province of death, and cause of death in respect of the 41 mothers who died in the two years that registered highest mortality(2003)(2004)) are summarised in Table4. It should be stressed here that 32% of deaths were of foreign origin, 57% were aged 35 years and over, 20% of deaths occurred in

		Coefficient (Standard Error)	RR (95% CI) a	P-value
	Period: 1996 -2005	0.04 (0.03)	1.04 (0.98-1.10)	0.181
	Maternal Age:			< 0.001
	35 to 44 vs. ≤ 34	1.05 (0.18)	2.90 (2.01-4.06)
	≥ 45 vs. ≤ 34	4.50 (0.42)	89.2 (39.04-203.85)

a Relative Risk.

only one province (Málaga). The mortality risk in Málaga, taking the maternal mortality ratio of others provinces as reference was 6 times higher (Rate Ratio 6.4 95%CI:2.6-14.2), and the mortality risk of death from foreign mothers, taking nationals mothers as reference was 3.1 times higher (Rate Ratio 3.1 95%CI:

Table 4 . Maternal Mortality Ratios, socio-demographic characteristics and causes of death as per ICD-10 in Spain (n: 41 maternal deaths; n: 896,472 live births): 2003-2004.

 4

					MMR
	Variables		N (%)	TLB (n)	(95%CI)
	Province of death
		Málaga	8 (19.5)	32,450	24.6 (10.6-48.6)
		Others*	33 (80.5)	864,022	3.8 (2.6-5.3)
	Age in years
		≤ 34	18 (43.9)	746,771	2.4 (1.4-3.8)
		35 to 44	21 (51.2)	149,049	14.1 (0.9-21.5)
		≥ 45	2 (4.9)	652	306.7 (34.4-1170.0)
	Nationality
		Foreign nationals	13 (31.7)	116,661	10.1 (0.6-1.9)
		Spanish nationals	28 (68.3)	779,811	3.6 (2.4-5.2)
	ICD-10 cause
	Pregnancy with abortive outcome.	O00-O08	4 (9.7)	896,472	0.4 (0.1-1.1)
	Oedema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperium.	O10-O16	10 (24.4)	896,472	1.1 (0.5-2.0)
	Maternal care related to the foetus and amniotic cavity and possible delivery problems.	O30-O48	5 (12.2)	896,472	0.5 (0.2-1.3)
	Complications of labour and delivery.	O60-O75	7 (17.1)	896,472	0.7 (0.3-1.6)
	Complications predominantly related to the puerperium.	O85-O92	10 (24.4)	896,472	1.1 (0.5-2.0)
	Other obstetric conditions, not elsewhere classified.	O95-O99	5 (12.2)	896,472	0.5 (0.2-1.3)

Total Live Births (TLB) *Others provinces deaths: Alicante, Almeria, Asturias, Badajoz, Balearic Isles, Barcelona, Cadiz, Ceuta , Jaén, Las Palmas, Lleida, Madrid, Murcia, Santa Cruz de Tenerife, Seville, Pontevedra, Valladolid, Zaragoza. Data source: INE, in-house.

Data source: National Statistics Institute (Instituto Nacional de Estadística -INE). In-house

Data source: INE, in-house

Competing interests: None.

Funding: None.

Contributors: MALF designed the study. All authors analysed and interpreted the data. MALF wrote the manuscript. All authors conducted background literature reviews and edited the paper.

Statement: "The Corresponding Author has the right to grant on behalf of all authors and does grant on behalf of all authors, an exclusive licence (or non exclusive for government employees) on a worldwide basis to the BMJ Publishing Group Ltd to permit this article (if accepted) to be published in JECH and any other BMJPGL products and sublicences such use and exploit all subsidiary rights, as set out in our licence (http://jmg.bmj.com/ifora/licence.pdf)."