Associations between the metabolic syndrome and retinal microvascular signs: the Atherosclerosis Risk In Communities study

PURPOSE: To examine the cross-sectional relationship of the metabolic syndrome (hypertension, hyperglycemia, central obesity, and dyslipidemia) and retinal microvascular abnormalities in middle-aged men and women. METHODS: A population-based, cross-sectional study involving 11,265 persons aged 49 to 73 years who had retinal photography from 1993 through 1995. Photographs were graded for presence of retinal microvascular signs (microaneurysms, retinal hemorrhages, arteriovenous nicking, and focal arteriolar narrowing) according to a standardized protocol. To quantify retinal vessel diameters, photographs were digitized and individual arteriolar and venular diameters were measured and summarized. The metabolic syndrome was defined according to the Third Report of the National Cholesterol Education Program Adult Treatment Panel. RESULTS: After adjustment for age, gender, race, education, cigarette smoking and alcohol consumption, persons with the metabolic syndrome were more likely to have retinopathy (odds ratio OR] 1.68, 95% confidence interval CI], 1.45-1.96), arteriovenous nicking (OR 1.30, 95% CI, 1.16-1.45), focal arteriolar narrowing (OR 1.24, 95% CI, 1.10-1.38), generalized retinal arteriolar narrowing (OR 1.23, 95% CI, 1.12-1.35), and generalized retinal venular dilatation (OR 1.30, 95% CI, 1.18-1.48) than persons without the metabolic syndrome. Associations for arteriovenous nicking, focal arteriolar narrowing, generalized arteriolar narrowing, and venular dilatation were noted, even in people without diabetes or hypertension. CONCLUSIONS: These data suggest that the metabolic syndrome is associated with microvascular changes in the retina. This finding reflects, in part, the associations of individual syndrome components with retinal microvascular abnormalities.