Black-white differences in risk of developing retinopathy among individuals with type 2 diabetes.

OBJECTIVE To assess racial differences in risk of developing retinopathy among individuals with type 2 diabetes, after taking into account differences in the distribution of risk factors for retinopathy. RESEARCH DESIGN AND METHODS The participants were 105 individuals with type 2 diabetes, aged 40-69 years, who had no evidence of retinopathy at the time of a diabetic eye disease screening project. After an average of 4 years of follow-up, the subjects were reevaluated using nonmydriatic funds photography. RESULTS Retinopathy occurred more often among black than white participants (50 vs. 19%). This difference could not be explained by differences in risk factors for retinopathy or potential confounders (odds ratio [95% CI] 2.96 [1.00-8.78] after adjustment for level of glycosylated hemoglobin, systolic blood pressure, type of diabetes treatment, and sex). CONCLUSIONS These results are consistent with the concept that racial differences in risk of developing retinopathy exist among individuals with type 2 diabetes and that these differences may be caused by differential (genetic) susceptibility to the adverse effects of increased levels of blood glucose and/or blood pressure. Discovery of the etiology of this differential susceptibility would allows us to identify and target secondary prevention efforts to individuals with type 2 diabetes who are at increased risk of retinopathy.