Adjusted mean (SE) within each sleep duration group (≤5, 6, 7, 8, and ≥9 hours) was calculated for a mean age (71.3 [4.7] years), mean years of education (16.6 [2.8] years), and non-Hispanic White male participants with an APOE ε33 allele genotype. CFI indicates Cognitive Function Index (score range: 0-15, with higher scores indicating worse reported cognitive function); DSST, Digit Symbol Substitution Test (score range: 0-91, with higher scores indicating correct responses in 90 seconds); and MMSE, Mini-Mental State Examination (score range: 0-30, with higher scores indicating better cognitive performance).