Prevalence of dementia and apoliprotein E genotype distribution in the elderly of Buttapietra, Verona Province, Italy

We investigated the prevalence of dementia and the apolipoprotein E (APOE) genotype distribution in the elderly of Buttapietra, a village near Verona, Italy. All residents over the age of 74 (n = 238), including those who were institutionalized, were studied using a direct-contact, single-phase design. The overall prevalence of dementia, clinically defined by DSM-III-R criteria, was 15.8 cases per 100 population, with age-specific figures increasing steeply with advancing age in both sexes. Alzheimer's disease (AD) was the most frequent dementing disorder (43%). APOE genotyping was determined after DNA amplification by restriction isotyping. We found that the epsilon4 allele and the epsilon3/epsilon4 genotype were associated with all types of dementia, although only the association of epsilon3/epsilon4 with AD reached statistical significance (odds ratio 4.5, 95% confidence interval 1.3-16.1). However, as reported in other Mediterranean countries, the frequency of the epsilon4 allele in our population was low (8.9%), suggesting that the population-attributable risk for AD, at least for elderly individuals (> or =75 years), could be small.