Physical activity, incidence and progression of age-related macular degeneration: A multi-cohort study.

PURPOSE: To investigate the impact of physical activity (PA) on the incidence or progression of age-related macular degeneration (AMD) in the general population. DESIGN: Meta-analysis of longitudinal cohort studies. METHODS: We included a total of 14,630 adults with no or early AMD at baseline from seven population-based studies and examined associations of PA with AMD incidence and progression using multi-state models (MSM) per study and subsequent random effects meta-analysis. Age effects were assessed using meta-regression. MAIN OUTCOME MEASURE: Hazard ratio (HR) for incident early or progression to late AMD. RESULTS: At baseline, mean age ranged from 60.7± 6.9 to 76.4 ± 4.3 years and prevalence of early AMD was 7.7%, ranging from 3.6 to 16.9% between cohorts. During follow-up, 1461 and 189 events occurred for early and late AMD, respectively. In meta-analyses, no or low to moderate PA (high PA as reference) was associated with an increased risk for incident early AMD (HR 1.19; 95%CI=[1.01, 1.40]; p=0.04), but not for late AMD. In subsequent meta-regression, we found no association of age with the effect of PA on incident AMD. CONCLUSIONS: Our study suggests high levels of PA to be protective for the development of early AMD across several population-based cohort studies. Our results establish PA as a modifiable risk factor for AMD and inform further AMD prevention strategies to reduce its public health impact