Role of APOE ε4 Allele and Incident Stroke on Cognitive Decline and Mortality

Abstract

Background

The Apolipoprotein E ( APOE) ε4 allele and stroke increase the risk of cognitive decline. However, the association of the APOE ε4 allele before and after stroke is not well understood.

Methods

Using a prospective sample of 3,444 (66% African Americans, 61% females, mean age = 71.9 years) participants, we examined cognitive decline relative to stroke among those with and without the APOE ε4 allele.

Results

In our sample, 505 (15%) had incident stroke. Among participants without stroke, the ε4 allele was associated with increased cognitive decline compared to non-carriers (0.080 vs. 0.036-units/year; p<0.0001). Among participants without the ε4 allele, cognitive decline increased significantly after stroke compared to before stroke (0.115 vs. 0.039-units/year; p<0.0001). Interestingly, cognitive decline before and after stroke was not significantly different among those with the ε4 allele (0.091 vs. 0.102-units/year; p=0.32). Poor cognitive function was associated with higher risk of stroke (HR=1.41, 95% CI=1.25–1.58), but the APOE ε4 allele was not (p=0.66). The APOE ε4 allele, cognitive function, and incident stroke were associated with mortality.

Conclusions

The association of stroke with cognitive decline appears to differ by the presence of the APOE ε4 allele, but no such interaction was observed for mortality.