Physical activity and the risk of cataract and age-related macular degeneration: a systematic review and meta-analysis of cohort studies.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational prospective cohort studies
PubMed 41814222 · doi:10.1186/s12886-026-04721-z
What was done
A systematic review and meta-analysis searched PubMed and Embase up to September 18, 2025, for prospective cohort studies assessing the relationship between physical activity and the risk of cataract and age-related macular degeneration (AMD). Random-effects models estimated summary relative risks (RRs) with 95% confidence intervals (CIs) for high versus low activity and per 20 MET-hours/week increment in leisure-time activity. Evidence certainty was assessed using World Cancer Research Fund (WCRF) criteria.
What was found
For cataract, 10 cohort studies (8 publications; 163,065 cases; 1,914,137 participants) yielded a summary RR of 0.90 (95% CI: 0.86–0.94, I2 = 74%) for high vs. low physical activity and 0.91 (95% CI: 0.84–0.99, I2 = 66%, n = 3) per 20 MET-hours/week increment (p-nonlinearity = 0.32; WCRF: probable). For AMD, 14 cohort studies (9 publications; 17,653 cases; 566,895 participants) yielded a summary RR of 0.92 (95% CI: 0.84–1.01, I2 = 60%) for high vs. low physical activity and 0.92 (95% CI: 0.74–1.13, I2 = 48%, n = 3) per 20 MET-hours/week (p-nonlinearity = 0.34; WCRF: limited-no conclusion). No publication bias was detected.
Why it matters
This review supports a modest protective association between physical activity and incident cataracts, but shows that prospective evidence remains insufficient to confirm an association with age-related macular degeneration.
Limits
The findings rely entirely on observational cohort studies with substantial statistical heterogeneity (I2 = 60% to 74%), leaving risk of residual confounding. Dose-response analyses were restricted to only 3 studies per outcome, and abstract data do not separate specific cataract or AMD subtypes or evaluate objective physical activity measures.
Cited by
- partial Lack of exercise accelerates age-related vision loss.