1. Dr Kate Glyn-Owen kate.glyn-owen@nhs.net MARRIAGE AND MORTALITY MPH DISSERTATION

2.  Longitudinal (prospective) cohort study  Cohort of men from Caerphilly, Wales or surrounding villages  Commenced in 1979  Original cohort of 2512 men aged 45-59 years  Baseline questionnaire and physical assessment from 1979-1983 (phase 1)  Follow up with questionnaires and assessments on four further occasions (phases 2-5) THE CAERPHILLY PROSPECTIVE STUDY

3.  Is there a protective effect of marriage on mortality in the Caerphilly Prospective Study men?  Is this protective effect mediated via pathways involving biological, psychosocial, cognitive, lifestyle, relationship or risk factors?  Wider aim = to identify modifiable variables suitable for public health intervention RESEARCH QUESTIONS

4.  Over a century of evidence that marriage confers a protective effect on mortality  Mortality rates 10-15% lower  All other groups of marital status (widowed, divorced, single) have higher relative risk of dying than those who are married  Some evidence that this difference in risk is increasing  Fewer couples are entering legal marriages in England and Wales  Logical that the protective mechanisms of marriage must be able to operate outside of marriage  Marriage certificate itself cannot be protective!  If mechanisms identified, public health professionals could use this information to improve health and reduce mortality PUBLIC HEALTH CONTEXT

5.  Mechanisms by which protective effect is conferred are not clearly understood  Protection or selection?  Benefit greater for men than women (2–5x)  Women have larger social networks  Women more ‘controlling’  Benefit increases with age  Longer duration of accumulated marriage = lower mortality risk  Effect of co-habiting not as strong as marriage LITERATURE SUMMARY

6.  Prospective studies have shown benefits of:  Stronger social relationships  Socioeconomic factors (women)  Health behaviours (men)  Experimental evidence of physiological associations with:  Cardiovascular, Endocrine and Immune system functions  Depression  Peridontal disease, dental caries  Exacerbation of RA and Parkinson’s disease activity LITERATURE SUMMARY

7.  STRENTHS  Detailed data on participants  100% follow up for mortality data (no follow-up bias)  Multivariate regression analysis allowed adjustment for multiple confounding variables  WEAKNESSES  Men only  Limited demographic group therefore results not generalisable  Relatively small (2099 men for whom marital status data available)  Data for all variables not available for all participants, further reducing sample size (random error)  Random error due to ‘snapshot’ data eg. Diet  No physical activity data STRENGTHS AND WEAKNESSES

8.  Existing data from Caerphilly Prospective Study used  No further ethics approval required  Statistical analysis performed using STATA 8.2  Binary variables constructed for marriage (1=married, 0=unmarried) and mortality (1=alive, 0=dead on 30 April 2006)  All other variables grouped into ‘blocks’  Biological factors  Psychosocial factors  Lifestyle factors  Risk factors  Cognitive factors  Social capital / relationship factors METHODS

9.  Bivariate analysis of mortality status against all other variables  Chi squared tests and ANOVA  Bivariate analysis of marital status against all other variables  Chi squared tests and ANOVA  Of the variables which were significantly associated with BOTH mortality and marital status:  Height, employment status and social class were included in all further analysis as confounding variables  All other modifiable variables were investigated in further analysis in order to explore their relationship with marital status and mortality STATISTICAL ANALYSIS CONT.

10.  Multivariate logistic regression analysis  Identify explanatory variables which might explain the significant relationship between marital status and mortality  Identify possible pathways by which the significant explanatory variables from the first analysis might be acting on mortality STATISTICAL ANALYSIS CONT.

11.  After adjusting for confounding variables the odds ratio for mortality for married men compared to all other groups of marital status was 0.60 (0.47, 0.78) p<0.001  After adjusting for confounding variables, compared to married men the odds ratios for mortality for other marital status groups are:  Single1.49 (1.01, 2.20)p 0.047  Widowed1.78 (1.12, 2.83)p 0.015  Divorced/separated1.77 (1.15, 2.74) p 0.010 RESULTS

12.  Cause of death  Marital status group was significantly associated with cause of death for respiratory disease and gastrointestinal disease  Divorced / separated men were on average more than twice as likely to die from respiratory disease than married men (odds ratio 2.35, 95% confidence intervals 1.19, 4.66, p = 0.014)  Single men were on average more than four times as likely to die from gastrointestinal disease than married men (odds ratio 4.09, 95% confidence intervals 1.49, 11.2, p = 0.006)  There were no significant differences between marital status groups for circulatory disease deaths or ‘other’ deaths RESULTS

13.  Adjusting for the following variables eliminated (and may therefore explain) the significant relationship between marital status and mortality:  National Adult Reading Test (NART)  Alcohol consumption  Total energy consumption (kcal)  Fruit consumption  Vegetable consumption  Vegetable fibre consumption  Sugar consumption  Of these variables, the following were significantly associated with mortality:  Sugar consumption (OR mortality 1.003 (1.000, 1.005) p<0.001)  Fruit consumption (OR mortality 0.97 (0.95, 0.99) p 0.001)  Vegetable consumption (OR mortality 0.96 (0.94, 0.98) p<0.001)  Vegetable fibre consumption (OR mortality 0.93 (0.90, 0.96) p<0.001)  NART – crystalised intelligence (OR mortality 0.98 (0.97, 0.99) p<0.001) RESULTS

15.  Married men consumed significantly more fruit, vegetables and vegetable fibre than all other groups  Fruit 3% reduction in mortality (95% CI 0.95, 0.99 p=0.001)  Vegetables 4% reduction in mortality (95% CI 0.94, 0.98 p<0.001)  Vegetable fibre 7% reduction in mortality (95% CI 0.90, 0.96 p<0.001)  Significant relationships with mortality all eliminated by adjusting for weight = likely mechanism by which these dietary variables impact on health  Consistent with current knowledge: obesity / overweight associated with many chronic diseases  NART remains significantly associated with mortality after adjusting for all risk factors RESULTS

16.  Adjusted odds ratios for mortality of married vs unmarried men consistent with previous literature  Adjusted OR 0.60 (0.47, 0.78) p<0.001  Adjusted odds ratios for mortality between marital status groups consistent with previous literature in UK / USA  Adjusted ORs: Widowed 1.78 > Divorced 1.77 > Single 1.49  Cultural differences eg. Japanese widowers  Intelligence (NART)  OR mortality 0.98 (0.97, 0.99) p<0.001  Mean scores phase 3 23.9 married vs 20.4 unmarried, p<0.001  Protection or selection? DISCUSSION

17.  Health Survey for England  Women eat more fruit and veg than men  Co-habitors eat more fruit and veg than single  Fruit and veg intake related to social class  Adjusting for social class in analysis shows additional effect  Husband and wives diets usually similar but change dramatically following death of spouse  WHO estimate 16 million DALYS worldwide due to low fruit and veg intake  Causes 31% of IHD and 11% of stroke worldwide  DH estimate increasing fruit and veg intake by half a portion per day could reduce overall deaths from chronic disease by 20%  Fruit and veg intake already a key public health target in the UK  5 a day campaign  National School Fruit scheme  ? Target public health messages towards single, widowed and divorced groups  may help to reduce the preventable disease burden associated with low fruit and vegetable intake

18.  Fruit and vegetable consumption intervention in African Americans  Multicomponent intervention, 20 months duration  Activities targeted at individual, social network and community levels  Predisposing, enabling and reinforcing factors targeted EVIDENCE FOR TARGETING INTERVENTIONS InterventionDelayed interventionDifference at follow-up P value BaselineFollow-upBaselineFollow-up Single3.563.463.403.180.280.29 Married3.724.473.743.660.810.0001 Widowed / divorced 3.894.733.743.770.960.0004

19.  Results of the EPIC Heart study: Fruit and vegetable intake and mortality from ischaemic heart disease  Adjusted for marital status RECENT WORK Fruit + veg intake, portions per day <33-45-7≥8 Married or cohabiting (%) 76.378.178.981.7

20. On this dataset  Survival analysis (Cox proportional hazards)  Physical activity variables  Cause of death by marital status: further investigation  Detailed cause of death (ICD10 codes) Other suggested work  Relationships outside of marriage  Marital trajectories over time  Cultural contexts  The nature of dietary change after death of a spouse FURTHER WORK

21.  Any questions? THANK YOU FOR LISTENING kate.glyn-owen@nhs.net