Smoking and CVD tied to higher mortality in men compared to women; finds study

Although some studies suggest that the recent reduction in the male:female mortality ratio is likely a result of improvements in men's health, lifestyle or occupational environments, others attribute it to women's changing societal roles and increasing mortality from diseases such as lung cancer, which have traditionally affected mostly men. Many studies have examined the potential impact of social, behavioural and biological factors on sex differences in mortality, but few have been able to investigate potential variation across countries.

L i f e s t y l e a n d health factors may partially account for excess mortality in men compared with women, but residual variation remains unaccounted for. Variation in the effect sizes across countries may indicate contextual factors contributing to gender inequality in specific settings.

The aim of this current study was to identify potential factors contributing to sex differences in mortality at older age and to investigate variation across countries.

This study included participants age ≥ 50 yr from 28 countries in 12 cohort studies of the Ageing Trajectories of Health: Longitudinal Opportunities and Synergies (ATHLOS) consortium. Using a 2-step individual participant data meta-analysis framework, we applied Cox proportional hazards modelling to investigate the association between sex and mortality across different countries. We included socioeconomic (education, wealth), lifestyle (smoking, alcohol consumption), social (marital status, living alone) and health factors (cardiovascular disease, diabetes, mental disorders) as covariates or interaction terms with sex to test whether these factors contributed to the mortality gap between men and women.

Data analysis revealed the following facts.

• T h e s t u d y i n c l u d e d 179044 individuals.
• Men had 60% higher mortality risk than women after adjustment for age (pooled hazard ratio [HR] 1.6; 95% confidence interval 1.5–1.7), yet the effect sizes varied across countries (I 2 = 71.5%, HR range 1.1–2.4).
• Only smoking and cardiovascular diseases substantially attenuated the effect size (by about 22%).

Observing the results, the team concluded that "this study highlights sex inequality in mortality at older age and the crucial contributions of smoking to excess mortality in men. Future research should investigate variation in life experience between men and women and underlying mechanisms across different societies.

"For the full article follow the link: doi: 10.1503/cmaj.200484

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