Physical activity linked to lower dementia risk

Sustained higher physical activity was associated with lower dementia risk and better cognitive outcomes.
*Prospective cohort study; Level 2 (OCEBM).

Citation

Li Y, Li Y, Liu Y, et al. Association of long-term physical activity levels with dementia risk and cognitive function in US adults: a prospective cohort study. Lancet Public Health. 2026;11:e530-e542.

Background

Prior studies suggest exercise may protect brain health, but many used short follow-up or a single activity measure. This study tested whether long-term activity patterns were linked with dementia and cognitive performance.

Patients

US female nurses and male health professionals. Exclusions included baseline dementia, stroke, cancer, Parkinson disease, missing activity data, or walking difficulty.

Intervention

Higher long-term total physical activity, walking, vigorous aerobic exercise, and weightlifting, assessed repeatedly by questionnaire.

Control

Lowest activity levels for each activity type.

Outcome

Dementia; objective cognitive function using the Telephone Interview for Cognitive Status and related tests; subjective cognitive decline score (0-7).

Follow-up Period

Up to 37 years for dementia; 13 years for objective cognition.

Results

OutcomeHigher activity comparisonAssociation
DementiaHighest vs lowest total activity quartileHazard ratio 0.72 (95% CI, 0.68-0.76)
DementiaHighest vs lowest walking tertileHazard ratio 0.76 (95% CI, 0.72-0.80)
DementiaHighest vs lowest vigorous exercise tertileHazard ratio 0.89 (95% CI, 0.85-0.93)
Subjective cognitive declineHighest vs lowest total activity quartileRelative risk 0.77 (95% CI, 0.73-0.80)
Objective cognitionHighest vs lowest total activity quartile1.15 fewer years of age-related cognitive difference

CI=confidence interval.

Main analyses used a 4-year lag to reduce reverse causation. Fatal and nonfatal dementia findings were generally consistent. No clear patient-important threshold was established for the cognitive score differences.

Limitations

Observational design cannot prove causation. Activity was self-reported. Dementia may have been under-reported. Participants were mostly White health professionals, limiting generalizability.

Funding

US National Institutes of Health; funder had no reported study role.

Clinical Application

Encourage sustained physical activity for brain health, while explaining benefits are associative and should complement standard dementia risk reduction counseling.