Although many studies have consistently shown that, in both AD and MCI patients, the cognitive function of ApoE ε4 carriers is worse than non-carriers and that carriers suffered faster recession of cognition (Okonkwo et al., 2010; Whitehair et al., 2010; Wattmo et al., 2011; Risacher et al., 2013; Vos et al., 2013; De Beaumont et al., 2016), there have been no definitive conclusions regarding the effects of ApoE polymorphisms upon cognitive functions in the normal population, perhaps due to the confounding effect of age. Here, APOE is linked to Alzheimer disease.