MAPT and type 2 diabetes mellitus: Regarding the impact of major confounders on p-Tau expression (Figs. S5–S7), all three p-Tau markers showed a positive correlation between the immunoreactive areas or the optic density and the Braak stage in both control and T2DM subjects, indicating that p-Tau levels increase as cognitive decline progresses (Figs. S5f, l, S6f, l, and S7f, l).