Incidence of dementia and major subtypes in Europe: A collaborative study of population-based cohorts. Neurologic Diseases in the Elderly Research Group.

The authors examined the association of incident dementia and subtypes with age, sex, and geographic area in Europe. Incidence data from eight population-based studies carried out in seven European countries were compared and pooled. The pooled data included 835 mild to severe dementia cases and 42,996 person-years of follow-up. In all studies a higher proportion of cases were diagnosed with AD (60 to 70% of all demented cases) than vascular dementia (VaD). The incidence of dementia and AD continued to increase with age up to age 85 years, after which rates increased in women but not men. There was a large variation in VaD incidence across studies. In the pooled analysis, the incidence rates increased with age without any substantial difference between men and women. Surprisingly, higher incidence rates of dementia and AD were found in the very old in northwest countries than in southern countries. This study confirms that AD is the most frequent dementing disorder in all ages, and that there is a higher incidence of dementia, specifically AD, in women than men among the very old. Finally, there may be regional differences in dementia incidence.