GFAP and Alzheimer disease: There was a significant difference between groups, accounting for age and sex, with elevated levels in AD for pTau217 (b = 0.64, SE = 0.11, t[57] = 6.03, p < 0.001), GFAP (b = 80.87, SE = 29.97, t[56] = 2.70, p < 0.01), and NfL (b = 13.04, SE = 3.09, t[56] = 4.21, p < 0.001) (Figure 6A–C).