Physical Activity and Amyloid-β Brain Levels in Elderly Adults with Intact Cognition and Mild Cognitive Impairment

Objectives To examine the associations between amyloid‐β brain deposition and physical activity (PA) in elderly adults without dementia and to investigate whether the association has a dose‐response relationship. Design Cross‐sectional study. Setting French community‐dwelling people. Participants Elderly adults with normal or mildly impaired cognition (mean age 74.7 ± 4.2; 60.4% female) with available information on current self‐reported PA and amyloid‐β brain deposition measured using positron emission tomography (PET) using the PET‐ligand florbetapir F 18 (n = 268). Measurements A standardized uptake value ratio (SUVR) was obtained for each subject. Participants were divided according to amyloid plaque cortical retention defined according to a SUVR cutoff of 1.10 (SUVR+ vs SUVR−). Results Bivariate and multivariate analyses showed that PA was not significantly associated with SUVR. SUVR+ and SUVR− participants did not differ in terms of volume (continuous PA variables) and levels (categorical PA variables) of PA. PA was not correlated with SUVR in apolipoprotein E ε4 carriers or noncarriers. PA was not associated with cognitive function. Conclusion Although PA protects against dementia, there is no solid evidence that this protection involves a reduction in amyloid‐β brain deposition. Further studies are needed to determine whether PA (ideally measured at several time‐points using objective measures) is involved in the pathophysiology of Alzheimer's disease.