EFFECTS OF A COMBINATION OF BETA-CAROTENE AND VITAMIN-A ON LUNG-CANCER AND CARDIOVASCULAR-DISEASE

Background. Lung cancer and cardiovascular disease are major causes of death in the United States, It has been proposed that carotenoids and retinoids are agents that may prevent these disorders. Methods. We co nducted a multicenter, randomized, double-blind, placebo-controlled pr imary prevention trial - the Beta-Carotene and Retinol Efficacy Trial - involving a total of 18,314 smokers, former smokers, and workers exp osed to asbestos. The effects of a combination of 30 mg of beta carote ne per day and 25,000 IU of retinol (vitamin A) in the form of retinyl palmitate per day on the primary end point, the incidence of lung can cer, were compared with those of placebo. Results. A total of 388 new cases of lung cancer were diagnosed during the 73,135 person-years of follow-up (mean length of follow-up, 4.0 years). The active-treatment group had a relative risk of lung cancer of 1.28 (95 percent confidenc e interval, 1.04 to 1.57; P=0.02), as compared with the placebo group. There were no statistically significant differences in the risks of o ther types of cancer. in the active-treatment group, the relative risk of death from any cause was 1.17 (95 percent confidence interval, 1.0 3 to 1.33); of death from lung cancer, 1.46 (95 percent confidence int erval, 1.07 to 2.00); and of death from cardiovascular disease, 1.26 ( 95 percent confidence interval, 0.99 to 1.61). On the basis of these f indings, the randomized trial was stopped 21 months earlier than plann ed; follow-up will continue for another 5 years. Conclusions. After an average of four years of supplementation, the combination of beta car otene and vitamin A had no benefit and may have had an adverse effect on the incidence of lung cancer and on the risk of death from lung can cer, cardiovascular disease, and any cause in smokers and workers expo sed to asbestos. (C) 1996, Massachusetts Medical Society.