Depression and dementia in relation to apolipoprotein E polymorphism in a population sample age 75+

The aim of this study was to define the co-occurrence of depression and dementia in relation to apolipoprotein E (APOE) polymorphism. Physicians extensively examined 806 persons aged 78 years and over. DNA was extracted from peripheral white blood cells, and APOE genotype was determined using a microsequencing method on microtiter plates. The prevalence of dementia was 22.8% and was found to increase with the number of ε4 alleles present. Depression was found in 11.4% of the demented subjects compared to 3.5% of the nondemented subjects. The overrepresentation of depression in demented subjects was found for each of the common genotypes. Depression was not strongly associated with APOE polymorphism. In spite of the association between dementia and APOE polymorphism, as well as dementia and depression, there was no association between APOE polymorphism and depression.