Background: Depression is a potential risk factor for mortality among the aged and it is also associated with other chronic diseases and unhealthy lifestyles that may also affect mortality. The purpose of this study was to investigate the association between depressive symptoms and mortality, controlling for health, nutritional status, and life-style factors.
Methods: A cohort of elderly people (N = 167) was followed-up for ten years. Information on socio-demographic characteristics, medical history, smoking, and alcohol consumption was collected. The primary outcome was all-cause mortality; the secondary outcome was cancer-specific mortality. The Geriatric Depression Scale (GDS-15) was used to assess depression. Using a multivariable Cox proportional hazards regression, we examined the association between depressive symptoms and mortality.
Results: Elderly people with depression (scoring above the depression cut-off of 7) had a 53% increased risk of mortality (relative risk (RR) 1.53; 95%CI: 1.05–2.24) compared to non-depressed subjects. The combination of depressive symptoms with smoking was associated with a particularly higher risk of mortality (RR: 2.61; 95%CI: 1.28–5.31), after controlling for potential confounders.
Conclusions: Depressive symptoms are associated with a significantly increased risk of all-cause mortality. The combination of depressive symptoms and smoking shorten life expectancy among the aged.