Gene Frequency, Racial Groups

To compare relative frequencies of apolipo-protein E (APOE) alleles in African-American and Caucasian populations and test associa-tions with cognition, we studied two commu-nity-based samples: one of 253 African Amer-icans and another of 466 Caucasians age 60– 84 years. Logistic regression, adjusting for age, sex, education, and history of hypertension and diabetes was used to associate APOE with five cognitive measures. The APOE-e4 allele frequency was 29.5 % in African Americans and 12.1 % in Caucasians. In the African Americans, no association was found between the presence of the APOE-e4 allele and any of the cognitive measures. Among Caucasians, APOE-e4 carriers performed more poorly on three of the five tests. We also report a considerably higher frequency of the APOE-e4 allele in our African-American sam-ple compared to other US-based studies. (Eth