This epidemiologic study has three Components: (1) to re-examine a large geographically-defined, well-characterized cohort of younger-onset diabetic persons in southwestern Wisconsin in order to determine the 15- year progression of diabetic retinopathy, and incidences of proliferative retinopathy, macular edema, loss of vision, diabetic renal disease, and amputation; to evaluate these conditions with respect to risk factors measured at previous examinations (e.g., glycosylated hemoglobin and blood pressure); and to investigate possible effects of medications which have become more widely used since the first examination (e.g., angiotensin converting enzyme inhibitors and humulin, etc.); (2) to compare the prevalence and incidence of diabetic retinopathy in diabetic persons studied in Wisconsin with those of other ethnic and racial groups using gradings of fundus photographs (all graded in Wisconsin) and risk factor or data from population-based studies in different communities in the U.S.; and (3) to quantitate the relationships of glycemia, blood pressure, and markers of """"""""severity of diabetes"""""""" (e.g., proliferative retinopathy and visual impairment) to cause-specific mortality in the younger- and older- onset Wisconsin population. Younger-onset persons will be examined in their communities in a mobile examining van. Refraction, visual acuity, intraocular pressure and blood pressure measurements will be obtained according to standardized protocols. Determination of proteinuria, creatinine, and glycosylated hemoglobin will be performed. Objective recording of retinopathy from stereoscopic fundus photography combined with a standardized grading of retinopathy will be used as in the previous examinations of the population. Grading of the stereoscopic photographs provides a sensitive and reproducible method for detection of the progression of retinopathy. The incidence and causes of visual impairment will be determined. The progression of retinopathy and incidence of renal disease and amputation will be evaluated with respect to duration and age at diagnosis of diabetes, changes in glycosylated hemoglobin level, blood pressure, use of angiotensin converting enzyme inhibitors, use of humulin, insulin-like growth factor, serum uric acid, and other systemic and ocular conditions as ascertained at the previous examination(s) in the younger-onset group. The vital status of all participants with regard to the severity of retinopathy and other risk factors or risk indicators will be determined. Differences in frequencies and in risk factors for diabetic retinopathy among ethnic groups may have implications for prevention. In this grant, we will compare rates of diabetic retinopathy, among Hispanics, American Indians, African-Americans, and non-Hispanic Whites in Wisconsin. We will analyze data to determine if differences among these groups are related to differences in levels of covariates. Data from this study will continue to be used for estimating the need for medical counseling and rehabilitative services, projecting medical care costs, measuring temporal trends, developing causal inferences, developing preventive strategies, and designing clinical trials related to diabetes and diabetic retinopathy.
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