Calcium Supplements May Not Prevent Bone Loss in Women With Breast Cancer
Supplementation has no effect on bone mineral density in clinical trials (August 27)
Women undergoing treatment for breast cancer are widely prescribed calcium and vitamin D supplements to prevent and manage osteoporosis, an unwanted side effect of breast cancer therapies. However, new research from Wake Forest Baptist Medical Center finds that the recommended daily doses of these supplements may not prevent loss of bone mineral density (BMD) in these women.
Researchers reviewed data from clinical trials that evaluated the effect of antiresorptive drugs on BMD and used the “before–after” data from the comparison group to assess changes in BMD in pre- and postmenopausal women. Overall, the results from 16 trials indicated that 500 to 1,500 mg calcium and 200 to 1,000 IU vitamin D — the doses commonly recommended — do not prevent the loss of BMD in women with breast cancer. Despite supplementation, women lost BMD in virtually every clinical trial reviewed.
The new findings were published online in Critical Reviews in Oncology/Hematology.
Women with breast cancer lose BMD at a higher rate than their healthier counterparts, increasing their risk of fractures, which are associated with significant declines in function and health-related quality of life, and in higher mortality rates.
Consequently, it is a common practice to prescribe calcium and vitamin D supplements to these women — a “low intensity” intervention that seems to make sense, said co-author Mridul Datta, PhD, although it's never been tested.
In the clinical trials reviewed, BMD was measured at the beginning and end of the studies, Datta said, so if the supplementation worked to prevent BMD loss, “you should be able to see that in the data, and we clearly didn’t.”
Source: Wake Forest Baptist Medical Center; August 27, 2013.