Vitamin E, C Use May Not Affect Risk for Age-Related Cataract in Men

Laurie Barclay, MD

November 09, 2010

November 9, 2010 — Long-term, regular use of vitamins E and C does not appear to affect the risk for age-related cataract in men, according to the final results from a randomized, double-masked, placebo-controlled trial reported in the November 8 issue of Archives of Ophthalmology.

"An estimated 20.5 million persons 40 years and older in the United States show some evidence of age-related cataract," write William G. Christen, ScD, from the Divisions of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School in Boston, Massachusetts, and colleagues. "...Vitamin E is a lipid-soluble antioxidant concentrated in lens fibers and membranes that may inhibit cataract formation by reducing photoperoxidation of lens lipids and stabilizing lens cell membranes. Vitamin C is located in aqueous compartments of lens membranes, where it may function as an antioxidant and protect lens proteases from photooxidative destruction."

The goal of the study was to determine whether supplementation with alternate-day vitamin E or daily vitamin C would affect the incidence of age-related cataract in a large cohort of men enrolled in the Physicians' Health Study II.

In the Physicians' Health Study II, 11,545 apparently healthy US male physicians at least 50 years old with no diagnosis of cataract at baseline were assigned to receive 400 IU of vitamin E or placebo on alternate days and 500 mg of vitamin C or placebo daily. The primary study endpoint was self-reported incident cataract causing a decrease in best-corrected visual acuity to 20/30 or worse and confirmed by medical record review.

There were 1174 confirmed incident cataracts after 8 years of treatment and follow-up, including 579 in the vitamin E–treated group and 595 in the vitamin E placebo group (hazard ratio [HR], 0.99; 95% confidence interval [CI], 0.88 - 1.11). Similarly, vitamin C was not associated with a reduction in cataract (593 in the treated group and 581 in the placebo group; HR, 1.02; 95% CI, 0.91 - 1.14).

"Long-term alternate-day use of 400 IU of vitamin E and daily use of 500 mg of vitamin C had no notable beneficial or harmful effect on the risk of cataract," the study authors write. "...There was no overall effect of vitamin E or vitamin C on any cataract subtype. The HRs tended to be lower in younger men assigned to the vitamin E group, particularly for the PSC [posterior subcapsular] subtype, but this finding should be interpreted with caution, particularly in view of the absence of an overall effect, and may have been due to chance."

Limitations of this study include possible lack of generalizability to less well-nourished populations and use of synthetic vitamin E. In addition, cataracts develop slowly for many years and may require even longer periods of treatment and perhaps treatment at earlier ages.

"In summary, these randomized trial data from a large population of middle-aged and older, generally well-nourished men indicate that long-term supplementation with high-dose vitamin E and vitamin C, either alone or in combination, has little effect on rates of cataract diagnosis and extraction," the study authors conclude.

The National Eye Institute and the National Institute on Aging, the National Institutes of Health, and BASF Corp supported this study. The study authors have disclosed no relevant financial relationships.

Arch Ophthalmol. 2010;128:1397-1405.

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