Education Moderates the Relation Between APOE ε4 and Memory in Nondemented Non-Hispanic Black Older Adults

Background: The APOE epsilon 4 allele is a well-known risk factor for Alzheimer's disease (AD). Previous research argues that higher education helps to preserve cognition in older adults with AD pathology because of its key role in cognitive reserve and resilience. Objective: To test if higher educational level buffers the effect of APOE epsilon 4 on cognition among older non-Hispanic Blacks. Methods: Participants were 849 non-demented older non-Hispanic Blacks (38.3% APOE epsilon 4+), who underwent a comprehensive neuropsychological evaluation. Multiple linear regression models tested the relationship between APOE epsilon 4 status and twelve cognitive measures with education (up to high school and beyond high school) as a moderator. Results: Education buffered the effects of the APOE epsilon 4 allele, such that there was no impact of APOE epsilon 4 status on word-list memory retention and working memory among participants with more than a high school degree. This pattern was not observed for ten other cognitive measures of verbal and visual episodic memory, semantic memory, executive function, and processing speed-although a similar trend was observed for switching ability in executive functioning. The buffering effect of education was stronger among women than men. Conclusion: Our findings suggest that genetic effects on late-life cognition may be modified by environmental factors such as educational attainment. These results are consistent with the framework of cognitive reserve such that engaging in cognitively enriching activities and acquiring skills and knowledge with more years of education may increase the capacity to maintain cognitive function despite high genetic risk for impairment.