Change in depressive status and mortality in elderly persons: results of a national longitudinal study

The authors aimed to investigate whether a change in depressive status was associated with a change in the risk of mortality in the elderly during a four-year follow-up period. Data came from the Survey of Health and Living Status of the Elderly in Taiwan. A cohort of 1784 men and women in Taiwan aged 65 or older who were assessed on two occasions in 1999 and 2003, and subsequently followed up until 2007. Depressive symptoms were assessed by the 10-item Center for Epidemiologic Studies Depression Scale (CES-D). The mortality risk of different depressive statuses was computed after adjustment for a variety of covariates. The data were further analyzed by gender and cause of death. Overall, chronic depression was associated with all-cause mortality (hazard ratio [HR], 1.66; 95% confidence interval [CI], 1.18-2.32) after 4 years of follow-up and controlling for covariates. When analyzing by gender, incident depression was associated with mortality in males only (HR=1.54; 95% CI=1.04-2.27). In females, only chronic depression was associated with a higher risk of mortality (HR=1.77; 95% CI=1.08-2.88). The increased risk of mortality with incident depression in males and chronic depression in females was attributed to non-cardiovascular disease (non-CVD) causes more than to CVD causes. In males, chronic depression predicted a higher incidence of CVD deaths. While chronic depression confers a greater risk of mortality in older women, incident depression predicts increased mortality in older men. The link between changing depressive status, gender, ethnicity and mortality warrants further investigation.