Investigators from the Beaver Dam Eye Study presented an evaluation of the role of vitamin intake in diabetic retinopathy at the 1998 annual meeting of the Society for Epidemiologic Research in Chicago (1). Past evaluations of The Nutritional Factors in Eye Disease Study (as part of the Beaver Dam eye Study), have provided some evidence of decreased risk of lens opacities associated with increased antioxidant intake (see earlier EduFacts: "Vitamin A and Cataracts: Reviewing the Data").

Methods:

In the recent report, the relationship of vitamins C and E (through diet and supplements) and the incidence and progression of diabetic retinopathy was explored. Beaver Dam Eye Study Participants with diabetes at baseline were asked to provide retrospective information on diet and supplements using a modified Block Food Frequency Questionnaire. Of 230 patients with diabetes at baseline, 166 patients provided this information and were followed for 5 years. Incidence and progression of retinopathy were determined by grading of fundus photos.

Results:

Incidence of retinopathy was 28% (47 of 166 participants). Odd's Ratios (relative risks) were computed for risk of retinopathy among those at the highest quintile level of each micronutrient vs. those at the lowest quintile level.

Multivariate analysis was performed to control for factors such as gender, insulin use, diastolic BP etc. Relative risk for highest quintile vitamin C intake level vs. lowest quintile was 0.6 - indicating a 40% decrease in risk (p=0.06 for trend). Overall citrus food intake at the highest quintile level had a relative risk of 0.2 compared with lowest quintile intake. This was an 80% reduction in risk (p=0.03). Vitamin E was not associated with lowered risk of retinopathy in this study. The authors suggested further research in this area.

References

• Millen AE, Mares-Perlman JA, Klein R, Klein BEK, et al. Relationship of Vitamins C and E To the Incidence and Progression of Diabetic Retinopathy. Am J Epidemiol 1998;147(11)(suppl., s53, Abstract Number 212) - Presented at the 31st Annual Meeting of the Society for Epidemiologic Research, 1998, Chicago.