Depression as a risk factor for the incidence of first-ever stroke in 85-year-olds.

Background And Purpose: Depression may increase the risk for stroke. Few studies have examined whether depression increases the risk for stroke in the very old and among the demented. We examined the relation between depression in 85-year-olds and the 3-year incidence of first-ever stroke.

Methods: A representative sample of 494 85-year-olds (147 demented, 347 nondemented) in Gothenburg, Sweden, was examined with psychiatric examinations and key informant interviews. Diagnoses of depression and dementia were made according to the Diagnostic and Statistical Manual of Mental Disorders, Third Revision. The sample was followed for 3 years regarding the incidence of stroke. Information on stroke was obtained from the Swedish Hospital Discharge Register, death certificates, self-reports, and key informants. Those with known stroke history at baseline (n=93) were excluded from the incidence study.

Results: The prevalence of depression at age 85 was 19%. Depression at baseline (hazard ratio, 2.7; 95% CI, 1.5 to 4.7; P=0.0006) and systolic blood pressure (hazard ratio, 1.014 per 1 mm Hg; 95% CI, 1.00 to 1.03; P=0.019) were related to increased incidence of first-ever stroke during follow-up. Depression increased stroke risk both among demented and nondemented individuals. Among the symptoms of depression, only depressed mood was an independent predictor of incidence first-ever stroke in multivariate analyses. Stroke history at age 85 was not associated with clinical depression.

Conclusions: Depression and stroke are both common in elderly populations. The finding that depression increases risk for first-ever stroke indicates that detection and treatment of depression may have implications for stroke prevention.