Physical activity and brain aging in Sub-Saharan Africa: A scoping review of observational studies

Physical activity may delay cognitive decline, but evidence from Sub-Saharan Africa (SSA) remains limited. This review summarizes findings on associations between physical (in)activity and brain aging in SSA, identifies research gaps and limitations, and proposes steps to strengthen research capacity. We searched five databases including PubMed using pertinent keywords. Observational studies conducted in SSA that examined physical (in)activity or related variables such as exercise as predictors and brain aging outcomes such as cognitive impairment or dementia were included. The review followed the PRISMA-ScR guidelines. Of 10,880 identified records, 19 studies met the inclusion criteria (18 cross-sectional, 1 longitudinal). Sample sizes ranged from 70 to 5,011 participants. Studies varied in design and assessment of exposures and outcomes. Seven studies reported associations between physical inactivity or lower physical activity levels and less favourable brain aging outcomes, including increased risk of cognitive impairment. Three studies found associations between higher physical activity or physical function and more favourable brain aging outcomes. Nine studies reported no associations between physical (in)activity and brain aging. Overall, the limited number of available studies, most of which were cross-sectional, leaves major gaps in understanding the role of physical (in)activity in brain aging across SSA. The evidence base is methodologically heterogeneous, with inconsistent assessment methods, limited consideration of contextual factors, and lack of longitudinal data, precluding conclusions regarding causality. This highlights the need for longitudinal research within a coordinated research ecosystem in SSA to generate robust evidence that can inform policy and support healthy brain aging across the region.