Association Between Brain β-Amyloid and Frailty in Older Adults

Background We sought to determine whether cortical and regional beta-amyloid (A beta) were cross-sectionally and prospectively associated with change in frailty status in older adults. Methods We used data from 269 community-dwelling participants from the Multidomain Alzheimer's Preventive Trial (MAPT) who were assessed for brain A beta using positron-emission tomography scan. Regional and cortical-to-cerebellar standardized uptake value ratios were obtained. Frailty was assessed by a frailty index composed of 19 items not directly linked to cognition and Alzheimer's disease. Results A significant and positive cross-sectional and prospective relationship was found for A beta in the anterior putamen (cross-sectional: beta = 0.11 [0.02-0.20], p = .02; prospective: beta = 0.11 [0.03-0.19], p = .007), posterior putamen (cross-sectional: beta = 0.12 [0.009-0.23], p = .03; prospective: beta = 0.11 [0.02-0.21], p = .02), and precuneus regions (cross-sectional: beta = 0.07 [0.01-0.12], p = .01; prospective: beta = 0.07 [0.01-0.12], p = .01) with increasing frailty. Conclusions This study has found new information regarding cross-sectional and prospective positive associations between region-specific brain A beta deposits and worsening frailty. The potential mechanisms involved require further investigation.