Prevalence and risk factors of diabetic retinopathy in adult and elderly subjects. The Casteldaccia Eye Study

PURPOSE: To investigate the prevalence and risk factors of diabetic retinopathy in subjects aged 40 years or older living in Casteldaccia, Sicily. METHODS: A population-based survey was performed on 1,588 subjects randomly enrolled among people aged 40 years or older. A total of 1,068 persons could be examined and in 1,019 the fundus of the eye was adequately observed (64.2% of the enrolled population). Diabetic retinopathy was diagnosed by ophthalmoscopy and fundus photographs; fluorescein angiography was performed in 91% of retinopathic subjects. In addition, a case-control study was carried out in order to demonstrate the association of diabetic retinopathy with a number of variables. RESULTS: Diabetic retinopathy was found in 4.4% of the whole population studied and in 34.1% of the diabetics. Nonproliferative diabetic retinopathy was found in 29.6% and proliferative diabetic retinopathy in 4.5% of the diabetics. Diabetic retinopathy was significantly associated with the following univariate variables: duration of diabetes, duration and type of antidiabetic treatment, and duration of alcohol intake. After multivariate logistic regression the only variable independently associated with diabetic retinopathy was duration of antidiabetic treatment. CONCLUSION: Diabetic retinopathy affects more than one third of diabetics and represents a leading cause of retinal disease. The antidiabetic treatment is the most important risk factor for diabetic retinopathy, even stronger than the duration of diabetes.