Background: Increasingly, researchers have begun to explore the association between depression and mortality. The current study examined the association between depressive symptoms and all-cause and cause-specific mortality in Chinese older people. Further to examine whether any associations were similar by sex and health status.
Methods: We used the Chinese version of the 15-item Geriatric Depression Scale to measure depressive symptoms (Geriatric Depression Scale score ≥ 8) and Cox regression to examine the association with all-cause and cause-specific mortality in a population-based cohort study of all 56,088 enrollees, aged 65 years or older, from July 1998 to December 2000 at all 18 Elderly Health Centers of Department of Health of Hong Kong. The cohort was followed up for mortality till December 31, 2005.
Results: Depressive symptoms were associated with all-cause mortality (hazard ratio 1.21, 95% confidence interval: 1.08-1.37) in men only (p value for sex interaction <.05) and with suicide mortality in men (hazard ratio 2.81, 95% confidence interval: 1.13-7.01) and women (hazard ratio 2.40, 95% confidence interval: 1.18-4.82) but not with other major causes of death after adjusting for age, education, monthly expenditure, smoking, alcohol drinking, physical activity, body mass index, health status, and self-rated health. The associations did not vary with health status.
Conclusions: Depressive symptoms were associated with all-cause mortality in men and with suicide in both sexes. Randomized controlled trials concerning the effects of treatment of depression on mortality are needed to clarify the causal pathways.