The association of atherosclerosis, vascular risk factors, and retinopathy in adults with diabetes: The Atherosclerosis Risk in Communities Study

Purpose: The aim of this report is to describe the prevalence of retinopathy and its associations with atherosclerosis and vascular risk factors in people with diabetes. Design: Cross-sectional study. Participants: Persons with diabetes, having gradable fundus photographs, from a biracial population-based cohort of adults (ages 51-72 years), and living in four United States communities (Forsyth County, North Carolina; the city of Jackson, Mississippi; suburbs of Minneapolis, Minnesota; and Washington County, Maryland) were studied from 1993 to 1995. Methods: Lesions typical of diabetic retinopathy were detected by grading a 45° color fundus photograph of one eye of each participant, using a modification of the Airlie House classification system. Main Outcome Measure: Severity of diabetic retinopathy (none, minimal nonproliferative, moderate non-proliferative, severe nonproliferative, and proliferative) and macular edema. Results: Retinopathy was detected in 328/1600 (20.5%) of those with diabetes; 114/1724 (6.6%) had hard exudate, 28/1600 (1.8%) had proliferative diabetic retinopathy, and 27/1662 (1.6%) had macular edema. The prevalence of diabetic retinopathy was higher in blacks (27.7%) compared with whites (16.7%). Controlling for duration of diabetes, serum glucose, systolic blood pressure, and type of diabetes medications taken, severity of retinopathy was associated with carotid artery intima-media wall thickness (odds ratio [OR]/0.1-mm thickness 1.09; 95% confidence interval [CI], 1.01, 1.17; P = 0.01), serum albumin (OR/0.1 g/dl 0.94; 95% CI, 0.88, 0.99; P = 0.02), but not race (OR blacks versus whites, 1.24; 95% CI, 0.88, 1.75; P = 0.21). Severity of diabetic retinopathy was not associated with coronary artery disease or stroke history or any of the plasma lipids studied. Controlling for age, gender, duration of diabetes, serum glucose, and type of diabetes medications taken, the presence of retinal hard exudates was associated with plasma low-density lipoprotein cholesterol (OR/10 mg/dl 1.18; 95% CI, 1.09, 1.29; P < 0.001), and plasma Lp(a) (OR/10 mg/dl 1.02; 95% CI, 1.00, 1.05; P = 0.04) but not race or blood pressure. Conclusions: These data suggest that plasma lipids are associated with the presence of hard exudate and that carotid artery intima-media wall thickness is associated with retinopathy, but other manifestations of atherosclerosis and most of its risk factors are not associated with severity of diabetic retinopathy.