Several lines of evidence indicate that depression is importantly associated with cardiovascular disease end points. However, little is known about the role of depression in stroke mortality.
This study examined the association between depressive symptoms and stroke mortality in a prospective study of behavioral, social, and psychological factors related to health and mortality in a community sample of 6676 initially stroke-free adults (45.8% male; 79.1% white; mean age at baseline, 43.4 years) from Alameda County, California. Depressive symptoms were assessed by the 18-item Human Population Laboratory Depression Scale. Cox proportional hazards regression models were used to evaluate the impact of depressive symptoms after controlling for age, sex, race, and other confounders.
A total of 169 stroke deaths occurred during 29 years of follow-up. Reporting 5 or more depressive symptoms at baseline was associated with increased risk of stroke mortality, after adjusting for age, sex, and race (hazard ratio, 1.66; 95% confidence interval, 1.16-2.39; P<.006). This association remained significant after additional adjustments for education, alcohol consumption, smoking, body mass index, hypertension, and diabetes (hazard ratio, 1.54; 95% confidence interval, 1.06-2.22; P<.02). Time-dependent covariate models, which allowed changes in reported depressive symptoms and risk factor levels during follow-up, revealed the same pattern of associations.
This population-based study provides the strongest epidemiological evidence to date for a significant relationship between depressive symptoms and stroke mortality. These results contribute to the growing literature on the adverse health effects of depression.