Racial Differences in the Prevalence of Diabetes but Not Diabetic Retinopathy in a Multi-ethnic Asian Population

Abstract

To compare the prevalence and risk factors of diabetes (DM) and diabetic retinopathy (DR) in a multi-ethnic Asian population of Chinese, Malays, and Indians in Singapore. A total of 2919 individuals participated in a population-based, cross-sectional study in Singapore of Chinese (n = 1633), Malays (n = 658), and Indians (n = 628) aged 40 to 95 years, with retinal photographs, graded using the Early Treatment Diabetic Retinopathy Study (ETDRS) severity scale. DM was defined as fasting plasma glucose ≥ 7 mmol/L, self-reported physician-diagnosed diabetes, and use of glucose-lowering medication. The overall age-standardized prevalence of diabetes was 13.8% (Chinese, 11.5%; Malays, 17.1%; and Indians, 21.6%; P < 0.0001). Among persons with diabetes (n = 401), the overall age-standardized prevalence of DR was 25.4% (20.1%, 24.8%, and 28.9% in Chinese, Malays, and Indians, respectively; P = 0.290). In multivariate analysis, longer diabetes duration (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.01-1.09, per year increase), higher glycated hemoglobin (OR 1.25; 95% CI, 1.01-1.54, per 1% increase), and serum creatinine levels (OR, 1.01; 95% CI, 1.00-1.03, per mg/dL increase) were the independent risk factors of DR in the whole population. Race was not found to be associated with DR (OR, 1.35; CI, 1.00-1.83). The associations of major risk factors with DR were similar among the three ethnic groups. There was a significant difference in the prevalence of diabetes between Chinese, Malays, and Indians. The main risk factors of DR, similar among the three ethnic groups, are longer diabetes duration, higher hbA1c, and higher creatinine levels. No significant racial differences were found in the prevalence of DR among persons with diabetes.