Purpose: To study whether the metabolic syndrome is associated with retinopathy independent of the presence of diabetes.
Design: Nationally representative, population-based, cross-sectional study.
Methods: The association between the metabolic syndrome and retinopathy was studied in persons 40 years of age and older with gradable fundus photographs in the Third National Health and Nutrition Examination Survey (NHANES III). Fundus photographs were graded for retinopathy, and clinical and laboratory data were used to define the metabolic syndrome. Logistic regression was performed using the presence of the metabolic syndrome or one of the metabolic syndrome components as the independent variable and with the presence of retinopathy as the dependent variable. The main outcome measures were the odds ratios (OR) of retinopathy in persons with the metabolic syndrome, analyzed both for the total NHANES III population (n = 8,205) and for those in the nondiabetic population (n = 6,582).
Results: 5.4% of all persons and 3.5% of nondiabetic persons from the civilian noninstitutionalized United States population 40 years of age and older had retinopathy, as estimated from NHANES III sample. The relationship between the metabolic syndrome and retinopathy (OR, 2.23; 95% confidence interval [CI], 1.69 to 2.95) disappeared in analyses stratified by diabetes status. Among the nondiabetic population, there was no association between the metabolic syndrome and retinopathy (OR, 1.23; 95% CI, 0.77 to 1.99), but there was an association between high blood pressure and retinopathy (OR, 1.61; 95% CI, 1.09 to 2.37).
Conclusions: In this population-based, cross-sectional study, there was no evidence of an association between the metabolic syndrome and retinopathy independent of diabetes status. Prospective studies are warranted to determine the significance of the metabolic syndrome for predicting risk of ocular and systemic disease independent of diabetes.