Homozygosity for the APOE E4 allele is solely associated with lower cognitive performance in Brazilian community-dwelling older adults: the Bambuí Study.

Objective: To investigate if APOE E4 allelic status is associated with the cognitive functioning of elderly individuals. Methods: Participants (n = 1,408) from the Bambuí Cohort Study of Aging were selected based on the results from both variables (APOE genotype and MMSE score). Gender, age, education, marital status, skin color, GHQ score and biological measures were used as confounding factors for adjusting the logistic regression. Results: The population was in Hardy-Weinberg equilibrium, and the APOE E4 allele frequency was 13.4%. APOE E4 allele homozygosity conferred a superior odds ratio (OR) for cognitive impairment (OR = 3.1) compared to E4 allele heterozygosity (OR = 0.99) even when adjusted for age, sex, education, marital status, skin color, triglycerides, HDL, systolic pressure, and GHQ (OR = 2.9). No differences were observed between the other covariates. Conclusions: The APOE E4 allele was observed to have a dramatic effect on cognitive impairment, especially in homozygotes, which comprised approximately 2% of the population.