Retinopathy is a major complication of diabetes, and although intensive glucose control can reduce its incidence and progression, the effect is limited. Other factors associated with diabetes, such as obesity, may also be relevant. Obesity results in a variety of metabolic disorders that can influence retinopathy and other microvascular complications of diabetes.1
Although diabetes is associated with retinopathy, a population-based study in Rochester, Minnesota, of patients with type 2 diabetes found that within this cohort, obesity was an independent and modifiable risk factor for developing retinopathy (hazard ratio, 2.01; 95% CI, 1.35-3.13).2 This study differed from others that did not find obesity related to retinopathy by defining obesity by relative weight instead of body mass index (BMI, calculated as weight in kilograms divided by height in meters squared). For example, in the Wisconsin Epidemiologic Study of Diabetic Retinopathy, obesity when defined by BMI criteria was not independently associated with the incidence or progression of retinopathy in persons with type 2 diabetes over a 10-year period.3 Similarly, in the Hoorn Study, no statistically significant association of BMI with the incidence of retinopathy was found in persons with type 2 diabetes.4