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Beta‐carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers
Author(s) -
Tanvetya Tawee,
Bepler Gerold
Publication year - 2008
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.23527
Subject(s) - medicine , beta carotene , lung cancer , odds ratio , confidence interval , relative risk , cancer , multivitamin , incidence (geometry) , randomized controlled trial , vitamin , physics , optics
BACKGROUND Some studies have suggested that beta‐carotene supplementation may increase the risk of lung cancer, particularly among smokers or former smokers. Beta‐carotene, a provitamin A, is available in multivitamins. In the current study, the authors investigated the risk of lung cancer associated with beta‐carotene in smokers or former smokers and surveyed the beta‐carotene content in national brand multivitamins. METHODS The authors systemically reviewed the published literature using a search of the MEDLINE database and performed a meta‐analysis of large randomized trials that reported on the effect of beta‐carotene supplementation on the incidence of lung cancer among smokers or former smokers. A sample of multivitamins was evaluated for their beta‐carotene content and the suggested daily dosage. RESULTS Four studies contributing 109,394 subjects were available for analysis. The average daily beta‐carotene dosage in these trials ranged from 20 to 30 mg daily. Among current smokers, beta‐carotene supplementation was found to be significantly associated with an increased risk of lung cancer (odds ratio [OR], 1.24; 95% confidence interval [95% CI], 1.10–1.39). Among former smokers, there was no significant increase noted (OR, 1.10; 95% CI, 0.84–1.45). In a sample of 47 common multivitamins, beta‐carotene was present in 70% of the identified formulas. The median dosage of beta‐carotene was 0.3 mg (range, 0–17.2 mg) daily. The beta‐carotene content was found to be significantly higher among multivitamins sold to improve visual health than among other multivitamins, with a median daily dosage of 3 mg (range, 0–24 mg). CONCLUSIONS High‐dose beta‐carotene supplementation appears to increase the risk of lung cancer among current smokers. Although beta‐carotene was prevalent in multivitamins, high‐dose beta‐carotene was observed among multivitamin formulas sold to promote visual health. Cancer 2008. © 2008 American Cancer Society.