Objective: To study the association between white matter lesions (WML) in specific locations and the risk of dementia.
Design: The Rotterdam Scan Study, a prospective population-based cohort study. We scored periventricular and subcortical WML on magnetic resonance imaging and observed participants until January 2002 for incident dementia.
Setting: General population.
Participants: We included 1077 people aged 60 to 90 years who did not have dementia at baseline.
Main outcome measure: Incident dementia by Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM III-R) criteria.
Results: During a mean follow-up of 5.2 years, 45 participants developed dementia. Higher severity of periventricular WML increased the risk of dementia, whereas the association between subcortical WML and dementia was less prominent. The adjusted hazard ratio of dementia for each standard deviation increase in periventricular WML severity was 1.67 (95% confidence interval, 1.25-2.24). This increased risk was independent of other risk factors for dementia and partly independent of other structural brain changes on magnetic resonance imaging.
Conclusion: White matter lesions, especially in the periventricular region, increase the risk of dementia in elderly people.