Leisure exercise lowers dementia risk

A systematic review and meta-analysis led by researchers at the University of Southern California, published in The Lancet, analyzed 74 observational studies involving over 4.2 million adults across 30 countries. The study found that leisure-time physical activity was associated with a 24% lower risk of all-cause dementia, while occupational physical activity was associated with a 20% higher risk. The findings highlight the 'physical activity paradox,' suggesting that the context of physical activity matters for brain health. The study was led by Natan Feter and David Raichlen, with contributions from multiple international institutions. The research was funded by the United States — National Institutes of Health and other organizations. The authors caution that the observational nature of the studies limits causal conclusions, and that occupational activity may reflect broader social and environmental factors rather than movement itself.