GFAP and Alzheimer disease: Our aim was to determine which blood pressure metrics (e.g., systolic blood pressure, diastolic blood pressure, pulse pressure) most robustly relate to fluid biomarkers of brain aging in a cohort of functionally intact older adults, including astrocytic activation (GFAP), neuronal axon breakdown (NfL), and AD pathobiology (pTau181; Aβ42/40).