GFAP and Cognitive impairment: Increasing levels of NfL (β = −0.032 [SE, 0.013]; P = .01) and GFAP (β = −0.087 [SE, 0.025]; P < .001), but not the Aβ42/40 ratio (β = 0.006 [SE, 0.040]; P = .88) or pTau-181 (β = 0.026 [SE, 0.025]; P = .31), were associated with worsening cognitive function and incident mild cognitive impairment or probable dementia.