LONG-TERM VITAMIN-C SUPPLEMENT USE AND PREVALENCE OF EARLY AGE-RELATED LENS OPACITIES

We designed the present study to examine the cross-sectional relation between age-related lens opacities and vitamin C supplement use over a 10-12-y period before assessment of lens status in women without diag nosed cataract or diabetes. This design avoids biased measurement of n utrient intake that results when knowledge of lens opacities influence s nutrition-related behavior or its reporting. The participants were 2 47 Boston-area women aged 56-71 y selected from the Nurses' Health Stu dy cohort with oversampling of women with high or low vitamin C intake s. Lens opacities were graded with the Lens Opacification Classificati on System II. Use of vitamin C supplements for greater than or equal t o 10 y (n = 26) was associated with a 77% lower prevalence of early le ns opacities (odds ratio: 0.23; 95% CI: 0.09, 0.60) at any lens site a nd a 83% lower prevalence of moderate lens opacities (odds ratio: 0.17 ; 95% CI: 0.03, 0.85) at any lens site compared with women who did not use vitamin C supplements (n = 141) after adjustment for age and othe r potentially confounding variables. Women who consumed vitamin C supp lements for < 10 y showed no evidence of a reduced prevalence of early opacities. These data, together with data from earlier experimental a nd epidemiologic studies, suggest that long-term consumption of vitami n C supplements may substantially reduce the development of age-relate d lens opacities.