APOE and Alzheimer disease: After removing APOE4 status as a covariate, the model pCSF/FW/PVVS ∼ age + sex + Dx demonstrated a strong R2 = 0.632 and indicated that older subjects exhibited increased WM pCSF (age: t = 4.704, P < 0.001), and those with MCI/Alzheimer’s disease expressed a higher WM pCSF (DxNL: t = −3.145, P < 0.01) in Fig. 3A.