Résumé :
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[BDSP. Notice produite par INIST-CNRS YR0xedl3. Diffusion soumise à autorisation]. The protective relation of ascorbic acid and alpha-tocopherol to the development of diabetic retinopathy has not been thoroughly evaluated in epidemiologic studies. The association of prevalent diabetic retinopathy with serum ascorbic acid and alpha-tocopherol was studied among participants with type 2 diabetes (>=40 years) (n=998) in the Third National Health and Nutrition Examination Survey (1988-1994) ; 20% of the sample (n=199) had prevalent retinopathy. The overall odds ratio for retinopathy among participants in quartile 4 compared with quartile 1 for serum ascorbic acid was 1.3 (95% confidence interval : 0.8,2.3), with a p for trend=0.60 after adjustment for the confounders of smoking, race, waist/hip ratio, hypertension, and duration of diabetes. The overall odds ratio for retinopathy among participants in quartile 4 compared with quartile 1 for serum alpha-tocopherol was 2.7 (95% confidence interval : 1.6,4.6), with a p for trend=0.14 after adjustment for confounders. After removal of supplement users of vitamin C (n=307) or vitamin E (n=298), the odds ratio changed direction or was attenuated : adjusted odds ratios for retinopathy among participants in quartile 4 compared with quartile 1 for serum ascorbic acid and alpha-tocopherol=0.7 (95% confidence interval : 0.3,1.4) and 1.6 (95% confidence interval : 0.9,2.9), respectively. In summary, no significant associations were observed between serum levels of major dietary antioxidants and retinopathy. Recent use of supplements for treatment of complications of diabetes may explain the direct associations.
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