A newly published report has questioned the value of recommended doses of calcium and vitamin D supplements for men at risk for lower bone mineral density because of their use of androgen deprivation therapy (ADT) for prostate cancer.
An article by Datta and Schwartz in the July issue of The Oncologist (along with a media release from Wake Forest Baptist Medical Center) points out that the doses of calcium and vitamin D that have been tested to date in men receiving ADT are not, in fact, adequate to prevent loss of bone mineral density. By contrast, we do know that high levels of dietary calcium and calcium supplement use are associated with higher risks for cardiovascular disease and advanced prostate cancer.
Loss of bone mineral density is a significant consequence of long-term ADT in men with prostate cancer. The use of calcium and/or vitamin D supplements in such men men is encouraged by lay and professional groups (and it makes perfect theoretical sense). So Datta and Schwartz carried out a systematic review of currently available guidelines for the use of calcium and vitamin D supplements and the results of clinical trials of calcium and vitamin D supplementation on bone mineral density in men with prostate cancer who were undergoing ADT.
Here are their findings:
- There have been no trials at all conducted to date that tested the comparative effects of calcium and/or vitamin D supplementation as compared to no supplementation in men with prostate cancer undergoing ADT.
- Data from 12 published clinical trials (including 2,399 men with prostate cancer undergoing ADT) show that these men actually lost bone mineral density over time (at recommended, daily calcium doses of 500–1,000 mg/day and at recommended, daily doses of vitamin D of 200–500 IU/day).
In the media release from Wake Forest Baptist Medical Center, Mridul Datta, PhD is quoted as saying that:
Calcium and/or vitamin D supplementation to prevent loss of bone mineral density in these men seems so logical that no one had questioned whether it works.
He continues by saying that:
We used [our] data to determine whether calcium and vitamin D supplements prevented bone loss in these men. The answer clearly is, ‘No.’
The wakeup call of these findings is that the presumption of benefit from calcium and vitamin D supplements that have been routinely recommended to these men must be rigorously evaluated.
There have long been differences of opinion about the value (if any) of specific dose levels of calcium and vitamin D in the management of men with prostate cancer, the most appropriate formulation(s) of vitamin D supplements, and other related factors. However, Datta and Schwartz are correct in their assessment of the situation. We don’t actually have the data to be able to know, with accuracy, whether any supplementation is better than none or whether higher levels of supplementation might produce more beneficial effects. We have lots of opinions … but opinions aren’t facts.