Stroke and dementia risk: A systematic review and meta‐analysis

Abstract

Introduction Stroke is an established risk factor for all‐cause dementia, though meta‐analyses are needed to quantify this risk. Methods We searched Medline, PsycINFO, and Embase for studies assessing prevalent or incident stroke versus a no‐stroke comparison group and the risk of all‐cause dementia. Random effects meta‐analysis was used to pool adjusted estimates across studies, and meta‐regression was used to investigate potential effect modifiers. Results We identified 36 studies of prevalent stroke (1.9 million participants) and 12 studies of incident stroke (1.3 million participants). For prevalent stroke, the pooled hazard ratio for all‐cause dementia was 1.69 (95% confidence interval: 1.49–1.92; P < .00001; I² = 87%). For incident stroke, the pooled risk ratio was 2.18 (95% confidence interval: 1.90–2.50; P < .00001; I² = 88%). Study characteristics did not modify these associations, with the exception of sex which explained 50.2% of between‐study heterogeneity for prevalent stroke. Discussion Stroke is a strong, independent, and potentially modifiable risk factor for all‐cause dementia.