Objective: This study determined the influence of depressive symptoms on subsequent mortality of all causes.
Method: The Honolulu Heart Program, established in 1965, is a prospective, community-based cohort of Japanese American men living in Hawaii. The analysis was based on 3,196 Japanese American men aged 71-93 at the time of the fourth examination in 1991-1993. Depressive symptoms were measured by use of an 11-question version of the Centers for Epidemiologic Studies Depression Scale questionnaire. All-cause mortality data were available for 6 years of follow up. Data were analyzed on the basis of presence or absence of chronic diseases.
Results: The overall prevalence of frequent depressive symptoms was 9.9%. Age-adjusted mortality rates at 3 years were 48.0 and 30.3 per 1,000 person-years for the depressed and nondepressed groups, respectively. At 6 years, the rates were 54.1 (depressed) and 41.5 (nondepressed) per 1,000 person-years. After adjustment for age, marital status, and antidepressant use, the relative risk for all-cause mortality associated with depressive symptoms was 1.53 for 3-year and 1.27 for 6-year mortality. Among participants who were healthy (without cognitive impairment, coronary heart disease, stroke, diabetes, or cancer), the association between depressive symptoms and mortality was greater (relative risk of 2.30 and 1.57 for 3- and 6-year mortality, respectively). Among participants with chronic disease, there were no significant associations between depressive symptoms and mortality.
Conclusions: Depressive symptoms are a risk factor for mortality in elderly people, particularly in physically healthy individuals.