In several reviews [24, 31, 40, 41], the potential of an interaction between alcohol use and the presence or absence of the apolipoprotein E ε4 allele (a known risk factor for AD [50] and other types of dementia [51]) and the resulting risk of either cognitive impairment or dementia was also examined, albeit based on a limited number of studies with substantial heterogeneity (see also [52]). This evidence concerns the gene APOE and dementia.