Overview
- Participants with the highest activity levels in midlife and in older age had roughly 41–45% lower risk of all-cause dementia, with similar reductions for Alzheimer’s disease.
- Activity levels reported in early adulthood showed no significant association with later dementia risk.
- Genetic analyses found midlife benefits primarily in non‑carriers of APOE ε4, while in later life higher activity was associated with reduced risk for both carriers and non‑carriers.
- Moderate and heavy activity in midlife appeared most protective, whereas in later life benefits were observed across activity intensities.
- The findings come from more than 4,200 Framingham Offspring participants followed for decades, using a self‑reported Physical Activity Index in a predominantly White cohort, and the observational design limits causal conclusions.