Association of APOE with Alzheimer’s disease in Mexico, Caribbean‐Hispanics, Peruvian and Mexican Americans

Abstract

AbstractBackgroundThe Apolipoprotein E (APOE) ε4 allele is the strongest genetic risk factor for Late Onset Alzheimer’s disease (LOAD). However, its genetic effect is heterogeneous across different ethnicities. We investigated the association of APOE with LOAD in five different Hispanic studies: Mexicans in the Mexican Health and Aging Study (MHAS), Caribbean Hispanics in the Washington Heights Inwood Aging project (WHICAP), Peruvians in the Genetics of Alzheimer’s disease In Peruvian Populations (GAPP) and Mexican Americans from The Health & Aging Brain among Latino Elders (HABLE) and the Texas Alzheimer’s Research and Care Consortium (TARCC).MethodA total of 7,832 participants were included in the analysis. APOE genotypes were generated by direct genotyping or imputation. SNPs associations with LOAD were assessed using multivariate logistic regression models in PLINK. Analyses were adjusted for age (≥60 years old), sex, and education. Global ancestry proportions, Native Americans, European, African were estimated with ADMIXTURE software using the Human Genome Diversity Project as the reference panel. Genetic ancestry specific secondary analyses were conducted using the same models.ResultThe genetic ancestral composition was significantly different across cohorts. Peruvians and Mexicans showed a predominant native ancestry, Caribbean‐Hispanics appeared to have a major contribution of European ancestry, and Mexican Americans exhibited similar proportions of both European and Native ancestries. We observed a significant association with e4 allele dosage in all the cohorts, except for MHAS. The genetic effect of at least one copy of the e4 allele on LOAD risk was very similar in GAPP and HABLE (OR = 3.42, SE = 0.39 and OR = 3.33, SE = 0.33, respectively), while attenuated in TARCC (OR = 2.81, SE = 0.28) and WHICAP (OR = 1.82, SE = 0.16). Among MHAS participants with a predominant European ancestry, APOE association achieved statistical significance with an increased disease risk (OR = 3.42, SE = 0.55) for homozygous carriers. Within the native‐prevalent ancestry subsample, the increased LOAD risk among APOE_ e4 heterozygous carriers were similar in both GAPP and HABLE cohorts (OR = 3.61, SE = 0.44 and OR = 3.64, SE = 0.43, respectively).ConclusionOur results showed a differential risk for LOAD from the APOE_ e4 allele across populations with admixed genetic ancestry.