GFAP and Mental deterioration: Stable-positive groups for Aβ42/40, pTau217, GFAP, and NfL demonstrated steeper cognitive decline in global cognition (and all other cognitive domains) compared with the stable-negative group (estimate [SD] time × biomarker status β = −0.07 ± 0.02, P < .001 for Aβ42/40; −0.08 [0.02], P < .001 for pTau217; −0.08 [0.02], P < .001 for GFAP; and −0.08 [0.01], P < .001 for NfL).