Memory performance and the apolipoprotein E polymorphism in a community sample of middle-aged adults

Abstract

The apolipoprotein E genotype (APOE) is an established risk factor for Alzheimer disease, with the age-at-onset occurring earlier in individuals having at least one APOE ε4 allele, relative to the APOE ε3 or APOE ε2 isoforms. Moreover, nondemented older adults with the APOE ε4 allele also show diminished cognitive performance, particularly on tests of learning and memory, and an accelerated decline in memory performance with increasing age. The current investigation extends the study of the APOE ε4 allele and cognitive performance to healthy, middle-aged adults. A community sample of 220 non-Hispanic Caucasian men and women, aged 24-60 (average age = 46), were genotyped for the APOE polymorphism and completed a battery of neuropsychological tests. Multivariate analyses were conducted on measures of verbal learning and memory (e.g., learning a list of words and recalling them 30 min later), visual memory (e.g., reproducing a previously copted figure from memory), and attention span (e.g., repeating long lists of digits), after adjustments for age, and estimated IQ. Results indicated that performance on learning and memory tasks was significantly poorer in adults having any APOE ε4 allele, relative to adults with APOE ε2 and ε3 genotypes (P