Some human and preclinical studies have supported the idea that DM may cause cognitive impairment and dementia by impairing brain structure and metabolism, e.g., amyloid β (Aβ), tau, and glucose metabolism, as well as insulin signals and cerebrovascular dysfunction (Jayaraman and Pike, 2014; Gonzalez-Reyes et al., 2016; Shinohara and Sato, 2017; Sutherland et al., 2017; Beeri and Bendlin, 2020; Rasool et al., 2021). The gene discussed is MAPT; the disease is diabetes mellitus.