Education and the incidence of dementia in a large population-based study: the Rotterdam Study.

We assessed the risk of dementia by educational level in a prospective population-based study. In the Rotterdam Study, 6,827 nondemented participants with known education level were followed for an average of 2.1 years. During this period, 137 new cases of dementia occurred. Low education was associated with higher dementia risk in women but not in men, suggesting that the association is modified by sex. Our data indicate that cross-sectional studies may overrate the association between education and risk of dementia.