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 apolipoprotein E ε33 allele genotype. BMI indicates body mass index (calculated as weight in kilograms divided by height in meters squared); GDS, Geriatric Depression Scale (score range: 0-15, with higher scores indicating higher depressive symptoms).