APOE and type 2 diabetes mellitus: Consistent with our previous findings that T2DM patients with MCI showed higher ApoE ε4‐carrying frequency and elevated GSK‐3β activity compared with those without cognitive impairments,12 we found here that ε4 (p = .03) but not ε2 carriers (p = .99) exhibited significantly increased GSK‐3β activity compared with the ε3 group (Figure 1C).