Although the APOE ε4 allele is one of the most well-established AD risk factors and the genetic variant that by far confers the strongest effect on disease risk [6,10,49], most studies of this association in non-EuroA populations have not precisely quantified for APOE genotype-associated risks for ε4 heterozygotes and ε4 homozygotes with notable exceptions of AAs [10,27], Caribbean Hispanics [50], Indians [51], and Han Chinese [52]. Here, APOE is linked to Alzheimer disease.