APOE and diabetes mellitus: There are many factors that increase the risk for dementia, including lack of social interactions (Kuiper et al., 2015), heart disease (Wolters et al., 2018), diabetes (Cheng et al., 2012), and genetic factors [the apolipoprotein E (APOE) ε4 allele] (Chen et al., 2009; Fernández-Calle et al., 2022).