Late-life depression in context of low neuroticism is risk factor for stroke: a 9-year cohort study

Objectives – Depression predicts stroke, however meta-analyses show significant heterogeneity. We hypothesise that the risk of depression on incident stroke is conditional upon the relative contribution of vascular disease and of neuroticism in the underlying pathways to depression in a specific patient. We examined whether depression increases stroke in persons with low neuroticism and without pre-existing cardiac disease Methods – Population-based cohort study with 9-year follow-up (n=2050; ≥ 55 years, 52% female). The incidence of stroke was determined by self-report data as well as data from general practitioners and death-certificates. Neuroticism was measured using the Dutch Personality Questionnaire (DPQ) and depression using the Center for Epidemiological Studies-Depression Scale (CESD). All data were analysed by Cox proportional hazards regression. Results – 117 incident cases of stroke occurred during follow-up. Among persons with a history of cardiac disease (n=401), depression predicted incident stroke independent of neuroticism-level with a hazard rate (HR) of 1.05 [95% CI: 1.01 – 1.10] (p=.02). In persons without cardiac disease (n=1649), depression and neuroticism interacted significantly in predicting incident stroke (p=.028). Stratified analyses showed that depression predicted incident stroke in those with low neuroticism: HR =1.05 [95% CI: 1.00 – 1.09] (p=.033), but not in those with high neuroticism: HR =1.01 [95%: 0.96 – 1.05] (p=.82). Conclusions In persons without pre-existent cardiac disease, depression is only predictive for future stroke in absence of high neuroticism. This might be explained by the hypothesis that late-life depression in context of low neuroticism is a marker of subclinical vascular disease.