Depression, vascular factors, and risk of dementia in primary care: a retrospective cohort study

Abstract

Objectives: To study the interaction between and timing effects of depression and vascular disorders on dementia risk.

Design: Retrospective cohort study.

Setting: Primary care practices in the south of the Netherlands.

Participants: Individuals in primary care aged 50 to 100 followed for 13 years (N = 35,791).

Measurements: Medical diagnoses of incident depression, hypertension, obesity, type 2 diabetes mellitus, stroke, and dementia were extracted from a research database. Cox proportional hazards regression was used to test whether incident depression predicted dementia and its putative interactions with vascular factors.

Results: In total, 1,680 participants developed dementia. Individuals with depression (n = 978) had a higher risk of dementia (adjusted hazard ratio (HR) = 2.03, 95% confidence interval (CI) = 1.56-2.64). Depression exerted most effect in participants with incident stroke (HR = 5.29, 95% CI = 2.52-11.14) or newly diagnosed hypertension (HR = 3.09, 95% CI = 1.54-6.20).

Conclusion: Depression in later life increases the risk of dementia. The effect is particularly high in individuals with depression and vascular disorders. Targeting late-onset depression in individuals with vascular disorders might lower dementia risk by preventing cerebrovascular changes.

Keywords: dementia; depression; epidemiology; hypertension; stroke.