APOE and major depressive disorder: No correlation of miR-206 with potential confounding factors was identified within the MCI group including gender (p = 0.155) (Figure 3A), age (p = 0.847, r2 = 0.041) (Figure 3B), APOE genotype (p = 0.849) (Figure 3C), hypertension (p = 0.524) (Figure 3D), depression (p = 0.380) (Figure 3E), exercise (p = 0.813) (Figure 3 F), and diabetes (p = 0.367) (Figure 3G).