Impact of APOE ε4 on the Cognitive Performance of a Sample of Non-Demented Puerto Rican Nonagenarians

APOE epsilon 4 is a major risk factor for Alzheimer's disease. It has also been associated with cognitive impairment and cognitive decline in young-olds, but the impact of the epsilon 4 allele on cognitive function in very late life is still unclear. The object of this study was to evaluate the association of the epsilon 4 allele of APOE with the cognitive performance of a sample of non-demented oldest-olds. Eighty-seven Spanish-speaking Puerto Rican non-demented nonagenarians were administered a complete neuropsychological assessment and provided a blood sample used for APOE genotyping. A factor analysis generated two factors: 1) verbal memory; and 2) visuo-spatial, naming and attention tasks, accounting for 43.6% of the overall variance in the 13 original neuropsychological variables. The multivariate analysis reflected, after controlling for gender, education, and age, the APOE epsilon 4 carriers performed better in overall cognition (both factors analyzed together) than non-carriers (T-2 = 0.082, F(2, 80) = 3.289, p = 0.042). Neither gender nor the gender by APOE epsilon 4 status interaction was associated with differences in cognition. In conclusion, the results of this study suggest that, among these Puerto Rican non-demented nonagenarians, being an APOE epsilon 4 allele carrier is associated with better cognition.