APOE and Parkinson disease: Following adjustment for confounding variables such as age, sex, education level, APOE ε4 carrier status and PD duration, the study noted that CSF GFAP had cross-sectional correlations with CSF Aβ42 (β = 0.162, p = 0.035), T-tau (β = 0.337, p < 0.001), P-tau (β = 0.375, p < 0.001), and α-syn (β = 0.311, p < 0.001) (Additional file 1: Table S2).