The ε4 allele of the apolipoprotein E (APOE) gene is a prominent risk factor for Alzheimer's disease (AD), but its implication in other dementias is less well studied.
We used a data set on 2858 subjects (1098 AD, 260 vascular dementia [VaD], 145 mixed AD and VaD, 90 other dementia diagnoses, and 1265 controls) to examine the association of APOE polymorphisms with clinical dementia diagnoses, biomarker profiles, and longevity.
The ε4 allele was associated with reduced longevity as ε4 versus ε3 homozygotes lived on average 2.6 years shorter (P = .006). In AD, ε4 carriers lived 1.0 years shorter than noncarriers (P = .028). The ε4 allele was more prevalent in AD, mixed AD and VaD, and VaD patients compared to controls, but not in other dementia disorders.
The APOE ε4 allele is influential in AD but might also be of importance in VaD and in mixed AD and VaD, diseases in which concomitant AD pathology is common.