Systolic blood pressure dipping may be associated with mobility impairment and brain volume in community-dwelling older adults: An exploratory study
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Objective: We investigated whether systolic blood pressure (SBP) dipping is associated with mobility outcomes and brain volume in older adults without dementia. Methods: We conducted an exploratory analysis of data from 345 community-dwelling older adults (mean age [SD]: 69.9 [7.1], 60% women) who underwent 24-h BP measurement and mobility assessment. Mobility measures included usual and dual-task (DT) gait velocity, step length, and variability. For DT assessment, participants performed naming animals (NA) and serial sevens (S7) tasks. A subsample of participants (N = 32) also underwent magnetic resonance imaging to estimate total grey matter, white matter, and hippocampal brain volumes. We conducted hierarchical regression models to examine the association between SBP dipping and mobility outcomes, after adjusting for age, years of education, sex, Montreal Cognitive Assessment score, body mass index, hypertension, diabetes, other cardiovascular diseases, musculoskeletal conditions, and study cohort. Similar models were conducted to investigate associations between SBP dipping and brain volumes. Results: SBP dipping significantly predicted gait velocity and step length under usual and both DT conditions. The R2 change was the highest for usual gait velocity (Fchange = 7.8, p = 0.005, R2change = 0.019), and lowest for step length during the NA task (Fchange = 4.4, p = 0.037, R2change = 0.01), suggesting a deleterious effect of SBP dipping on gait regardless of task complexity. For brain volumes, SBP dipping significantly predicted right hippocampal volume (Fchange = 5.4, p = 0.029, R2change = 0.12), and total hippocampal volume (Fchange = 5.1, p = 0.033, R2change = 0.1). Conclusions: Our findings suggest that SBP dipping, as a marker of cardiovascular disease in older adults, impacts mobility performance and hippocampal volume. SBP dipping could be targeted in future therapeutic interventions in older adults at risk for mobility and cognitive impairment.