Relationships between plasma GFAP and change in neurodegeneration (represented by hippocampal volume (B=−0.202, P=.013) and precuneus thickness (B=−0.039, P=.001), cerebral glucose metabolism (FDG-PET, B=−0.031, P=.150) and cognition (represented by Mini-Mental State Examination (MMSE, B=−0.722, P=.041) and Clinical Dementia Rating – Sum of Boxes (CDR-SOB, B=0.570, P=.013) were assessed using LMEMs, with covariates age and sex (and education for cognition) with family as a random effect. Unstandardised B and P-values were calculated using natural log GFAP. For this visualization, the cut-off for low/high GFAP was based on the optimal cut-point at Youden’s index (low (<87.5 pg/mL, black) and high (≥87.5 pg/mL, red)). P<.05 was considered as statistically significant.