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

Abstract

IntroductionThe well-known risk factors for the development of diabetic retinopathy are the duration of diabetes and diabetes control. Diabetes control plays a key role in the prevention of diabetic retinopathy [1] and it is known to influence the incidence and progress of diabetic retinopathy independent of age, diabetes type, diabetes duration and the severity of retinopathy [2,3]. Other modifiable risk factors, e.g. blood pressure, dyslipidemia and lifestyle factors such as smoking, alcohol use and physical activity, may also have a major impact in preventing diabetic retinopathy.There is some evidence that physical activity or exercise can have a protective impact against diabetic retinopathy. Physical activity has been shown to be protective or at least not promote development of diabetic retinopathy in type 1 diabetes [4]. In addition, work-related physical activity seems to confer some protection against the risk of diabetic retinopathy (OR 0.66, 95 % CI 0.51-0.85) as shown in the recent study by Tikellis et al. [5]. In the FinnDiane study, low-intensity physical activity was independently associated with an increased risk of proliferative retinopathy (OR 1.49, 95 % CI 1.15-1.93), but there was no association with the frequency of activity [6]. However, in some studies, the exercise level did not correlate with the progression of diabetic retinopathy [7] or proliferative diabetic retinopathy [8].The scanty information that exists on the association between alcohol and diabetic retinopathy is inconsistent. In a five-year prospective study, the risk of suffering any severity of diabetic retinopathy was significantly increased with daily alcohol consumption of 30 g or more (RR 2.25, 95% CI 1.15-4.42) [9]. In WESDR-study [10] a cross sectional-study revealed that moderate alcohol use decreased the prevalence of diabetic retinopathy in type 1 diabetics (OR 0.49, 95% CI 0.27-0.92), but in prospective population-based studies no such association was found [11,12]. In a recent study, moderate consumption of alcohol was not associated with either the presence (OR 0.91, 95% CI 0.62-1.35) or progression (OR 0.84, 95% CI 0.46-1.55) of diabetic retinopathy in patients with type 2 diabetes [13]. Furthermore, the study by Giuffre et al. observed no association in their multivariate model (OR 0.43, 95% CI 0.11-1.67 for alcohol consumption under 20 years), AbstractBackground: 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.