Alcohol Consumption, but Not Physical Activity or Smoking, Contribute To Advanced Forms of Diabetic Retinopathy: A Case-Control Study

Abstract

Background: Modifiable risk factors, like dyslipidemia and lifestyle factors such as smoking, alcohol use and physical activity, may have an impact in the prevention of diabetic retinopathy despite diabetes control and duration. Previous studies on the significance of alcohol consumption, physical activity/exercise and smoking, however, in diabetic retinopathy are conflicting. We investigated these lifestyle factors and their mutual interaction in diabetic retinopathy. Methods: This study is an observational, retrospective case-control study. The diabetic retinopathy group (DR) consisted of 182 patients with type 1 or type 2 diabetes and proliferative diabetic retinopathy or maculopathy. The patients were either laser-treated and/or had undergone vitrectomy. The control (DC) group comprised of 98 diabetic patients (type 1 or type 2) attending screening for diabetic retinopathy. They had very mild background or no retinopathy and their diabetes duration was at least 10 years. Results: The DC group was more physically active than DR, since 43% of DC group reported long-lasting regular physical activity compared with 25% in DR, respectively (p=0.001 (χ2)). In DR group, the amount of physical activity was inversely correlated with diabetic neuropathy (R= -0,159, p= 0.037), but not with diabetic nephropathy (R= -0.139, p= 0.66). Fifty percent of the DR group and 66 % of the DC group consumed alcohol occasionally with abstinence being reported by 42% of the patients in DR group and 23% in DC group (p was 0.017 (χ2)). Smoking habits did not differ significantly between the DR and DC groups. In multivariate logistic regression analysis, only alcohol consumption had significant association with DR (OR 0.331, 95% CI 0.147-0.748, p=0.008 for occasional alcohol consumption and OR 0.148, 95% CI 0.038-0.577, p=0.006 for regular alcohol consumption). Conclusions: Alcohol consumption seems to contribute to advanced forms of diabetic retinopathy. Although patients with DR are physically less active than DC, physical activity is not significantly associated with DR probably due to its correlation with neuropathy.