Association of Levels of Physical Activity With Risk of Parkinson Disease: A Systematic Review and Meta-analysis.
Level 3 - non-randomized controlled study
Systematic review of prospective observational cohort studies without randomized trials.
PubMed 30646166 · doi:10.1001/jamanetworkopen.2018.2421
What was done
A systematic review and dose-response meta-analysis (following MOOSE guidelines) searched PubMed, Embase, and Web of Science through February 2018 for prospective studies evaluating physical activity and incident Parkinson disease (PD). Diagnoses were confirmed by treating neurologists or authoritative medical records. Adjusted relative risks were pooled using random-effects models to assess overall associations and quantitative dose-response relationships per 10 metabolic equivalent of task (MET)-hours/week.
What was found
Eight prospective studies were identified, encompassing 544,336 participants, 2,192 incident PD cases, and a median follow-up of 12 years (range 6.1–22.0 years). Comparing the highest to lowest activity levels, significant risk reductions were observed for total physical activity (relative risk [RR], 0.79; 95% CI, 0.68–0.91) and moderate-to-vigorous physical activity (RR, 0.71; 95% CI, 0.58–0.87). Light physical activity was not significantly associated with PD risk (RR, 0.86; 95% CI, 0.60–1.23). In dose-response analyses, each 10 MET-hours/week increase in total or moderate-to-vigorous activity in men reduced PD risk by 10% and 17%, respectively. No linear dose-response association was detected among women.
Why it matters
This study provides quantitative evidence that moderate-to-vigorous physical activity is linked to a lower incidence of Parkinson disease, highlighting a clear dose-response relationship in men.
Limits
The findings are based entirely on observational cohorts, meaning residual confounding and reverse causation (prodromal motor or non-motor PD symptoms reducing physical activity years before clinical diagnosis) cannot be excluded. The underlying studies relied primarily on self-reported activity rather than objective device-based measurement, and the biological or behavioral reasons for the lack of dose-response in women remain uncharacterized.
Cited by
- supports Epidemiological literature demonstrates that greater physical activity is associated with a decreased risk of developing Parkinson's disease.