Increased risk for dementia both before and after stroke: A population‐based study in women followed over 44 years

Abstract Introduction Longitudinal studies are needed to understand the long‐term associations between stroke and dementia. Methods A population sample of 1460 women without stroke or dementia at baseline was followed over 44 years, from 1968 to 2012. Information on stroke and dementia was obtained from neuropsychiatric examinations, key‐informant interviews, hospital registry, and medical records. Results During 44 years follow‐up, 362 women developed stroke and 325, dementia. The age‐specific incidence of the two disorders was similar. The incidence of dementia was higher in those with stroke than among those without (33.7% vs. 18.5%; age‐adjusted hazard ratio 1.44, 95% confidence interval 1.15–1.81). The increased risk of dementia started already 5 years before stroke, was highest 1 year after stroke, and continued more than 11 years after stroke. Discussion There is an increased risk for dementia both before and after stroke. This has implications for understanding the relation between the two disorders and for prevention of dementia and stroke.