Apolipoprotein E-associated risk for Alzheimer's disease in the African-American population is genotype dependent

As a part of our ongoing study on Alzheimer's disease (AD) in elderly African Americans, we obtained clinical assessment and apolipoprotein E (ApoE) genotype data on 288 individuals (including 60 with AD). The ApoE epsilon 4 allele frequency was significantly increased in AD patients compared with controls. The age-adjusted odds ratio (OR) for AD in epsilon 4 homozygotes was 4.83 (95% confidence interval [CI], 1.71-13.64) compared with the epsilon 3/epsilon 3 genotype, but the OR for AD with the epsilon 3/epsilon 4 genotype did not reach significance (1.20; 95% CI, 0.58-2.45). These findings suggest that the association between ApoE epsilon 4 and AD is weaker in African Americans than in whites.