Beta carotene does not affect cataract progression, study shows

BOSTON – Beta carotene does not affect cataract progression, according to a study. However, among current smokers at baseline, beta carotene seemed to attenuate excess risk of cataract by about 25%, authors noted.

In the 12-year study, William Christen, ScD, enrolled 22,071 male physicians between the ages of 40 and 84. Participants were randomly assigned to receive either 50 mg of beta carotene on alternate days or placebo. Main outcome measures included age-related cataract and extraction. For the purposes of the Physicians’ Health Study 1, the defining factor was an age-related lens opacity responsible for a reduction in best-corrected visual acuity to 20/30 or worse. In each of the two groups, 11% of participants were smokers at baseline.

A total of 2,015 cataracts were identified, and 1,177 cataract extractions were performed. In general, there was no significant benefit or harm on the risk of cataract development resulting from beta carotene supplementation. Similarly, there was no significant benefit or risk of beta carotene supplementation on cataract extraction. The duration of treatment had an effect on the relative risks of developing cataract, but the trend was not statistically significant.

Analyzing by subgroup, current smokers assigned to the beta-carotene group had a statistically significant reduced risk of cataract development of 26% compared with smokers in the placebo group. Similar results were observed for cataract extraction as well.

“For both cataract and cataract extraction, the reduction in risk among current smokers assigned to beta carotene was apparent during the early years of treatment and follow-up,” the researchers wrote in the March issue of Archives of Ophthalmology.