Vascular stiffness predicts plasma markers of neurodegeneration among older African Americans

BACKGROUND: Vascular health is a critical and potentially modifiable determinant of Alzheimer's disease (AD) risk, yet its contribution to early neurodegenerative processes remains incompletely understood, particularly among African Americans, who experience a disproportionate AD burden. Estimated pulse wave velocity (ePWV), derived from age and blood pressure, provides a scalable index of vascular stiffness. OBJECTIVES: To examine associations between vascular stiffness and plasma biomarkers of AD-related neurodegeneration in older African Americans. DESIGN: Cross-sectional observational study. SETTING: Community-based aging cohort study conducted at an academic research center. PARTICIPANTS: A total of 145 cognitively unimpaired older African Americans (mean age=71.18±6.83 years; 110 women). MEASUREMENTS: ePWV was calculated using validated equations based on age and blood pressure. Plasma biomarkers included phosphorylated tau217 (p-tau217; N=145), phosphorylated tau231 (p-tau231; N=126), glial fibrillary acidic protein (GFAP; N=126), neurofilament light chain (NfL; N=126), and amyloid-β42/40 ratio (Aβ42/40; N=126). Multivariable regression models adjusted for sex, education, pulse pressure, waist-to-hip ratio, global cognition, and hypertension status. RESULTS: Higher ePWV was significantly associated with higher plasma concentrations of p-tau217 (β=0.34, p=.006), GFAP (β=0.55, p