Extended Data Table 2.

Sensitivity analyses using multiple plasma GFAP cutoffs to determine astrocyte positivity

Abbreviations: Ast−: reactive astrocyte negative; Ast+: reactive astrocyte positive; GFAP: glial fibrillary acidic protein; s.d.: standard deviation; p-tau: phosphorylated tau. The highest β-estimate was obtained using GFAP cutoff calculated as the mean + 2.0 s.d. of controls devoid of Aβ pathology for all plasma p-tau epitopes. Covariates: age, sex, and cohort. We inverted the values for plasma Aβ ratio in the analysis to pool plasma Aβ and Aβ-PET levels together. P-values were computed using linear regression models adjusted by age, sex and cohort (when appropriate) for individuals classified as Ast− and Ast+. In addition, the Aβ burden × astrocyte reactivity status interaction was also computed.