1. Home>
2. Specialties>
3. General Medicine>
4. Summary and Comment

DISAPPOINTING NEWS ABOUT BETA CAROTENE....

When a recent Finnish trial showed that beta carotene supplementation was associated with an increase in lung cancer among smokers (see Accession Number 940422001 or N Engl J Med 1994; 330:1029), many of us wondered whether other studies would reach a different conclusion. We now have the results of two additional randomized trials.

In a study from Harvard, 22,000 male physicians took either 50 mg of beta carotene or placebo every other day for an average of 12 years; 11 percent of the population were current smokers, and 39 percent were former smokers. The 12- year rates of malignancy, stroke, myocardial infarction, and death were virtually identical in both groups. Beta carotene had no effect on the incidence of any specific neoplasm.

Another trial compared placebo and a combination of 30 mg of beta carotene plus 25,000 IU of vitamin A in over 18,000 current smokers, former smokers, and workers exposed to asbestos. The trial was stopped prematurely after a mean follow-up of four years: subjects who received supplementation had a significantly increased relative risk of lung cancer (1.28) and overall mortality (1.17). The increase in cardiovascular mortality (RR, 1.26) just failed to reach statistical significance.

Comment: According to an accompanying editorial, these results "should put to rest any remaining hopes that, for adults, beta carotene supplements may be an effective means of lowering the risk of cancer and cardiovascular disease."

— AS Brett

Published in Journal Watch General Medicine May 14, 1996

Citation(s):

Hennekens CH et al. Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease. N Engl J Med 1996 May 2 334 1145-1149.

• Original article (Subscription may be required)
• Medline abstract (Free)

Omenn GS et al. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med 1996 May 2 334 1150-1155.

• Original article (Subscription may be required)
• Medline abstract (Free)

Greenberg ER; Sporn MB. Antioxidant vitamins, cancer, and cardiovascular disease. N Engl J Med 1996 May 2 334 1189-1190.

• Original article (Subscription may be required)
• Medline abstract (Free)