Carolyn Vachani, RN, MSN, AOCN
Abramson Cancer Center of the University of Pennsylvania
Last Modified: June 9, 2006
This study looked at the question: would calcium and vitamin D supplements decrease risk of breast cancer ? 32,282 women were randomized to receive either 1000 mg calcium carbonate and 400 IU vitamin D or placebo. The women were postmenopausal, with no history of breast cancer for the past 10 years. The study was stopped after 7 years.
The study found no difference in the rates of invasive breast cancer (528 cases in Calcium/D group vs. 546 cases in the placebo group) or non-invasive breast cancer. They also reported no difference in joint pains, which was a secondary question of the study.
Several previous retrospective studies (looking back on Ca/Vit D use) did show a benefit. Possible explanations for the lack of effect on breast cancer incidence in this study include:
At the present time, Ca and Vit D supplementation can not be recommended to prevent breast cancer.