Study of 4.2 Million Links Job-Related Activity to 20% Higher Dementia Risk

3 articles · Updated · Newsweek · Aug 18

A Lancet Public Health meta-analysis of 74 studies across 30 countries found leisure-time exercise cut dementia risk by 24%, while occupational physical activity was associated with a 20% increase.
More activity did not mean more protection across all settings: leisure exercise showed progressively lower risk until benefits leveled off, while heavier job-related activity tracked with higher risk before plateauing.
Researchers said physically demanding work often comes with repetitive tasks, lower job control, pollution, noise and psychosocial stress—factors that may erode cognitive reserve and help explain the “physical activity paradox.”
The review followed adults aged 45 to 93 for a median 10 years, but it was observational and relied largely on self-reported activity, so it cannot prove active jobs cause dementia.
The authors said the findings could reshape dementia-prevention advice toward safer workplaces, more leisure time and better access to parks, trails and recreational facilities—not simply urging people to move more.