Physical activity and risk of diabetic retinopathy: a systematic review and meta-analysis

AimsDiabetic retinopathy (DR) is an important microvascular complication of diabetes mellitus (DM) and a leading cause of visual impairment and blindness among people of working age. Physical activity (PA) or exercise is critical and beneficial for DM patients, whereas studies evaluating the relationship between PA and DR have yielded inconsistent and inconclusive results. The American Diabetes Association's Standards of Medical Care in Diabetes has also pointed out the indeterminate roles of PA in DR prevention. The purpose of this systematic review and meta-analysis was to explore the association between PA and DR risk.MethodsMedline (accessed by PubMed), EmBase, and Cochrane Library were systematically searched for studies up to June 2018, and the reference lists of the published articles were searched manually. The association between PA and DR risk was assessed using random-effect meta-analysis.ResultsTwenty-two studies were included in this meta-analysis. PA was found to have a protective association with DR [risk ratio (RR)=0.94, 95% confidence interval (95% CI) 0.90-0.98, p=0.005] in diabetic patients, and the impact was more pronounced on vision-threatening DR (RR=0.89, 95% CI 0.80-0.98, p=0.02). Sedentary behavior could increase the risk of DR (RR=1.18, 95% CI 1.01-1.37, p=0.04). Moderate-intensity PA was likely to have a slight protective effect (RR=0.76, 95% CI 0.58-1.00, p=0.05).ConclusionPA is associated with lower DR risk, and more studies should focus on the causality between them.