Investigators examined the relationship between physical exercise and the development and progression of age-related macular degeneration (AMD). The studies included in the meta-analysis followed patients for a mean of 7 years to determine which levels of physical exercise, if any, led to the mitigation of the development or progression of AMD.
Study design
This was a meta-analysis of 7 population-based longitudinal cohort studies from Australia, Germany, France, and the Netherlands that examined the associations of physical activity with AMD incidence and progression. A total of 14,630 participants >50 years of age with no or early AMD were included. Physical activity was assessed using questionnaires and categorized into no, low, moderate, and high physical activity.
Outcomes
During the follow-up, 1461 patients without AMD developed early AMD, and 189 patients with early AMD progressed to advanced AMD. Low or moderate physical activity was associated with an increased risk for the development of early AMD but not for progression from early to late AMD. However, the investigators found that high levels of PA protected against the development of early AMD but did not affect progression from early to late AMD.
Limitations
Only a small number of patients (n = 189) progressed from early to advanced AMD, which may have limited the statistical power to determine the effect of physical activity on the incidence of advanced AMD. Additionally, physical activity was self-reported and subject to recall bias. The study did not consider risk factors such as socioeconomic status, diet, and genetics.
Clinical significance
This study underscores the importance of physical activity as a modifiable risk factor for the progression of early AMD. This is information any ophthalmologist, optometrist, and primary care physician can provide to patients routinely, particularly because we are in an era where the prevalence of AMD is increasing.