Post hoc analyses considering participant AAO independent of parental AAO confirmed the expected association of APOE genotype with AAO of AD (eTable 3 in the Supplement).23,24APOE ε4/4 carrier status was associated with an earlier-than-expected AAO (β = −5.87 [95% CI, −9.25 to −2.50]; P = .001) after controlling for other acquired and heritable factors (eTable 4 in the Supplement). Here, APOE is linked to Alzheimer disease.