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.