Contrasting associations of diastolic blood pressure with plasma amyloid, tau, and neurodegeneration biomarkers in the Health and Aging Brain Study-Health Disparities (HABS-HD)

BackgroundBlood pressure is a major modifiable risk factor for both cardiovascular disease and dementia, yet its relationship with blood-based biomarkers of Alzheimer's disease (AD) and neurodegeneration remains unclear.ObjectiveTo evaluate associations of systolic blood pressure, diastolic blood pressure (DBP), and pulse pressure with plasma biomarkers of AD and neurodegeneration, and to examine whether these associations differ across Non-Hispanic White, Non-Hispanic Black, and Hispanic participants.MethodsParticipants were 2636 cognitively normal older adults enrolled in the Health and Aging Brain Study-Health Disparities. Participants with hypotension or hypertensive crisis were excluded. The outcomes were plasma biomarkers including phosphorylated Tau181, phosphorylated tau217 (p-Tau217), amyloid-β 42 to 40 ratio, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP). Adjusted multivariable linear regression models evaluated associations between blood pressure measures and log transformed plasma biomarker concentrations. Additional models examined the American Heart Association blood pressure categories as a predictor.ResultsHigher DBP was associated with lower concentrations of neurodegeneration related plasma biomarkers, including p-Tau217, NfL, and GFAP, after correction for multiple comparisons. Analyses using American Heart Association blood pressure categories demonstrated that stage 1 and stage 2 hypertension were associated with lower GFAP concentrations compared with normal blood pressure, with patterns that were broadly consistent across racial and ethnic subgroups.ConclusionsIn this multi-racial ethnic cohort of cognitively normal older adults without hypotension or hypertensive crisis, higher DBP and clinical blood pressure categories were associated with lower levels of select plasma biomarkers of neurodegeneration (NfL and GFAP).