APOE and Alzheimer disease: Stratification by age-at-onset of AD demonstrated higher APOE ε4-associated ORs in the younger group (onset at 60–80 years old) compared to the older group (onset later than 80 years old) in both males and females as shown in Supplementary Table 4, suggesting a higher genetic risk conferred by APOE ε4 alleles among younger patients.