title: The effect of beta-carotene supplementation on serum vitamin D metabolite concentrations.
abstract: In the alpha-Tocopherol, beta-Carotene Cancer Prevention (ATBC) study, a large randomized placebo-controlled trial designed to test the cancer prevention effects of alpha-tocopherol (50 mg/day) and beta-carotene (20 mg/day), participants receiving supplemental beta-carotene had significantly higher rates of lung cancer than those not receiving beta-carotene. It has been hypothesized that the supplemental beta-carotene may have interfered with the synthesis of vitamin D and that the resulting lower concentrations of vitamin D contributed to the elevated cancer incidence. We evaluated whether supplementation with beta-carotene altered the serum concentrations of either 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D in the ATBC Study, by comparing on-study changes between baseline and follow-up serum samples among 20 randomly selected matched pairs of subjects from the beta-carotene and placebo groups. In a matched-pair analysis, the difference between the changes in both 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in the beta-carotene supplement and placebo groups were small and statistically nonsignificant. These results provide no evidence that beta-carotene supplementation interferes with the endogenous production of 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D and suggest that it is unlikely that an interaction between supplemental beta-carotene and vitamin D metabolites contributed to the modest increase in lung cancer incidence observed in the ATBC Study.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland 20892, USA. mf101e@nih.gov
authors.forename: D M
authors.initials: DM
authors.lastname: Freedman
authors.forename: J A
authors.initials: JA
authors.lastname: Tangrea
authors.forename: J
authors.initials: J
authors.lastname: Virtamo
authors.forename: D
authors.initials: D
authors.lastname: Albanes
mesh_terms: D000367:Age Factors; D000975:Antioxidants / Q000009:adverse effects*; D004347:Drug Interactions; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D016555:Matched-Pair Analysis; D010919:Placebos; D012621:Seasons; D018709:Statistics, Nonparametric; D013997:Time Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D019207:beta Carotene / Q000009:adverse effects*
chemical_list: D000975:Antioxidants; D010919:Placebos; D019207:beta Carotene; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; C104450:25-hydroxyvitamin D