Association of 24-Hour Blood Pressure Variability With Cognition and Brain MRI Markers of Structural Change in Adults in Mid- to Late-Life

BACKGROUND AND OBJECTIVES: ε4 status. METHODS: In a cross-sectional study, dementia-free participants aged 55-80, from the community-based Brain and Cognitive Health (BACH) study in Melbourne, Australia, completed 24-hour ambulatory BP monitoring (ABPM) and hospital-based assessments: office BP, blood collection, neuropsychological testing, and brain MRI. ABPM variables included mean BP and coefficient of variation for 24-hour, awake, and asleep periods. Composites for global cognition and executive function were calculated. MRI markers included white matter hyperintensities (WMHs), brain volumetrics, cerebral blood flow, white matter free water, diffusion along the perivascular space, and blood-brain barrier water exchange rate. The primary outcomes were global cognition and WMH. We sought to partially replicate associations between ABPM and cognition in the HYpertension and gut PERmeability (HYPER) study, where cognition was assessed with the digital NIH Toolbox. Linear regressions were adjusted for demographic and vascular risk factors, with coefficients representing SD change in outcome per SD increase in exposure. RESULTS: ε4 carriers only. In HYPER (27-73 years, median age = 63 years; 50% female; n = 76), asleep BPV was negatively associated with fluid cognition (β = -0.211, 95% CI -0.382 to -0.040). DISCUSSION: ε4 carriers.