APOE and infectious disease: Although these allele frequencies differed significantly from the Chen et al. (2010) cross-sectional study of a population in Kenya, the small sample size of this Kenyan study was insufficient for accurate comparison of intra-continental variation of APOE. The higher ɛ4 frequency in Africans has been attributed to selective advantage as protection against infectious disease (Corbo and Scacchp, 1999; Fujioka et al., 2014; Van Exel et al., 2017; Smith et al., 2019).