Journal of the National Cancer Institute
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J. Natl. Cancer Inst. · Nov 2008
Randomized Controlled TrialCalcium plus vitamin D supplementation and the risk of breast cancer.
Although some observational studies have associated higher calcium intake and especially higher vitamin D intake and 25-hydroxyvitamin D levels with lower breast cancer risk, no randomized trial has evaluated these relationships. ⋯ Calcium and vitamin D supplementation did not reduce invasive breast cancer incidence in postmenopausal women. In addition, 25-hydroxyvitamin D levels were not associated with subsequent breast cancer risk. These findings do not support a relationship between total vitamin D intake and 25-hydroxyvitamin D levels with breast cancer risk.