Apolipoprotein E genotype, vascular risk and early cognitive impairment inan African Caribbean population

A reduced risk of Alzheimer's disease (AD) associated with the apolipoprote in E (APOE) epsilon4 allele is reported in populations of African origin. I n order to clarify possible reasons for this, we examined the association b etween APOE genotype and early cognitive impairment in a community-based Af rican Caribbean UK population aged 55-75 years. APOE genotype was available for 202 participants, 57 (28%) of whom were classified as having relative cognitive impairment on a battery of neuropsychological tests. Cognitive im pairment was negatively associated with epsilon2 and positively but more we akly associated with epsilon4. Effects of both alleles increased markedly a fter age 70. The effect of epsilon4 was increased in combination with hyper tension, diabetes or lower educational attainment, but these factors did no t influence epsilon2 effects. Cholesterol and triglyceride levels partially explained effects of epsilon2, but did not account for those of epsilon4. A reduced association between epsilon4 and later AD in populations of Afric an origin is unlikely to be explained by reduced cognitive effects or by di fferential mortality. However, it may be accounted for by vascular comorbid ity. The different patterns of association between epsilon2 and epsilon4 al leles suggest different pathways of effect. Copyright (C) 2001 S. Karger AG , Basel.