TOMM40‐APOE haplotypes are associated with cognitive decline in non‐demented Blacks

INTRODUCTION The goal was to investigate effects of APOE-TOMM40-'523 haplotypes on cognitive decline in non-demented non-Hispanic Blacks (NHB), and determine whether effects differ from non-Hispanic Whites (NHW). METHODS The impact of zero to two copies of the '523-Short variant (S; poly-T alleles < 20) within apolipoprotein E (APOE) genotype on a composite measure of global cognition and five domains was examined. RESULTS In NHB with e3/e3 (N = 294), '523-S/S was associated with faster decline in global cognition (β = -0.048, P = 0.017), episodic memory (β = -0.05, P = 0.031), and visuospatial ability (β = -0.037, P = 0.034) relative to those without '523-S. For NHB e4+ (N = 182), '523-S/S had slower decline in global cognition (β = 0.047, P = 0.042) and visuospatial ability (β = 0.07, P = 0.0005) relative to '523-S non-carriers. NHB e4+ with '523-S also had a slower rate of decline than NHWs e4+ with '523-S. DISCUSSION '523-S/S has a different effect on cognitive decline among NHB dependent on APOE allele. Differences in the effect of e4-'523-S in NHB may explain prior mixed findings on e4 and decline in this population.