In a nested, case-control study involving 636 women diagnosed with incident breast cancer and 1,272 controls, increased 25(OH) vitamin D(3) serum concentrations were associated with a decreased risk of breast cancer (OR=0.73 for women in the highest tertile). Furthermore, women under 53 years of age at the time of blood sampling were found to have a significant inverse association between vitamin D status and breast cancer, while in premenopausal women the risk was reduced, but not significantly. The authors state, “Randomized intervention trials with vitamin D supplementation are required to confirm its benefits on breast cancer risk, but the maintenance of adequate vitamin D levels should be encouraged by public health policy.”
