GFAP and Alzheimer disease: At visit 1, the AD group showed similar concentrations as the HC group for Aß42/40 (model 1, Tukey adjusted mean difference [95% CI] = −0.007 pg/mL [−0.014; 0.001], P = 0.102), but higher p‐tau181 (1.39 pg/mL [0.56; 2.22], P < 0.001), GFAP (120 pg/mL [71; 169], P < 0.001), and NfL (19 pg/mL [8; 29], P < 0.001).