In a nested case-control design, the APOE genotype disclosure cohort was drawn from cognitively and neurologically healthy adults whose average age was in the 70s and who were enrolled in either a study of cognitive and neuroimaging changes associated with aging or a study to assess the impact of genetic testing on mood and health behaviors. Fifteen of the 74 participants (∼20%) in this cohort chose not to learn their APOE genotype and were enrolled in the nondisclosure cohort—a design that may have introduced confounding by indication, as the participants who had less desire to learn their APOE genotype may also have had less concern about their cognition. Disclosure, performed by a genetic counselor, covered the necessary topics, and notably, no participant requested additional counseling. Cognitive testing for the disclosure cohort was then performed some time after disclosure, ranging from 1 to 24 months (mean of 8 months). The control cohort of participants who did not know their APOE genotype was assembled from several memory center cohorts to match the disclosed group on age, years of education, cognition, and APOE genotype distribution.