Previous research suggests that depression is a risk factor for stroke. However, the reliability of much research is limited by the lack of documentation on the presence of preexistent cardiovascular disease and by the use of limited measures of depression or stroke.
To test the hypotheses that (1) clinically relevant depressive symptoms are an independent risk factor of incident stroke in cardiac and noncardiac patients and (2) more chronic and severe depressive symptoms are associated with incident stroke.
A cohort of elderly Dutch people (aged ≥ 55 years) was followed up for 9 years in the Longitudinal Aging Study Amsterdam (baseline measurements were taken in 1992 or 1993, and the study concluded in 2001 or 2002, respectively).
Randomly selected population-based sample (N = 2965) without a history of stroke.
Main Outcome Measures
The study end point was a first stroke (nonfatal or fatal). Depression was measured using the National Institute of Mental Health Diagnostic Interview Schedule and the Center for Epidemiological Studies–Depression Scale. Multivariate Cox proportional hazards regression analyses of stroke incidence were performed. The association of the chronicity and severity of depressive symptoms was studied in extended models with time-dependent variables.
The sample's mean (SD) age was 70.5 (8.7) years, 52.1% were women, and the mean (SD) follow-up was 7.7 (3.1) years. Inclusion of an interaction between cardiac disease and clinically relevant depressive symptoms improved the model for stroke (P = .03). In participants with preexistent cardiac disease, but not in participants without cardiac disease, clinically relevant depressive symptoms at baseline (hazard ratio [HR], 2.18; 95% confidence interval [CI], 1.17-4.09) and the severity (range, 0-60; HR, 1.08; 95% CI, 1.02-1.13) and chronicity (HR, 3.51; 95% CI, 1.13-10.93) of symptoms during follow-up were associated with stroke.
Preexistent cardiac disease moderates the association between depressive symptoms and incident stroke. In cardiac patients, baseline depressive symptoms and both the severity and chronicity of symptoms during follow-up are associated with incident stroke.