Prevalence and risk factors of diabetic retinopathy in non-Hispanic whites and Hispanics with NIDDM. San Luis Valley Diabetes Study.
Diabetic retinopathy (DR) is the leading cause of blindness in adults in the United States. Because photocoagulation can reduce the incidence of blindness from severe DR by approximately 50%, it is important to identify people at increased risk for DR so that appropriate treatment can be accomplished. Use of populations at increased risk for diabetes may identify groups at increased risk for complications. A recent report from the San Antonio Heart Study showed that Mexican Americans were at greater risk for servere DR than non-Hispanic Whites. To compare the prevalence of DR between non-Hispanics and Hispanics in southern Colorado, 279 people with non-insulin-dependent diabetes mellitus (NIDDM) were identified, and retinal photographs identified the presence and severity of retinopathy. The worse eye was used to classify the severity of DR for each patient. Ninety percent of the subjects (166 Hispanics and 85 non-Hispanic Whites) were classified by retinopathy level. The duration-adjusted prevalence of any DR was 41.8% in Hispanics and 54.1% in non-Hispanic Whites. Severe DR (preproliferative and proliferative) occurred in 18.5% of the Hispanics and in 21.3% of the non-Hispanic Whites. The odds ratio for any DR, comparing Hispanics with non-Hispanic Whites adjusted for other risk factors, was 0.40 (95% confidence interval = 0.21, 0.76). Other risk factors for the presence of any retinopathy included use of exogenous insulin, increased duration of diabetes, younger age at diagnosis, increased glycosylated hemoglobin level, and increased systolic blood pressure. These data suggest that, compared with non-Hispanic Whites, Hispanics in Colorado may be at decreased risk for diabetic retinopathy.