It seems like good medical advice â€" prescribing calcium and vitamin D supplements for men at risk of bone loss from hormonal treatment for prostate cancer.
After all, it is a recommended treatment for women at risk of bone loss, known as osteoporosis, as they go through menopause.
But researchers at Wake Forest Baptist Medical Center said in a recent study that the supplementation strategy failed to prevent bone loss. They also cautioned it could increase the risk of cardiovascular disease and aggressive prostate cancer.
The Oncologist published the study online in its July issue.
"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," said Mridul Datta, co-author of the study.
Androgen deprivation therapy (ADT) is the mainstay treatment for men with advanced prostate cancer because it reduces serum levels of androgen hormones on which most prostate cancers depend.
A side effect can be bone loss. The center said 10 percent of men affected with bone loss will experience a fracture within two years of therapy.
That reality has led physicians to recommend calcium and vitamin D supplements to potentially reduce the risk of bone loss.
Researchers reviewed the results of 12 clinical trials of supplemental calcium and/or vitamin D covering 2,399 men with prostate cancer undergoing ADT. They also reviewed the men's bone mineral density before and after treatment.
The study showed that at the recommended doses â€" 500 to 1,000 milligrams of calcium and 200 to 500 IU of vitamin D per day â€" men undergoing ADT still lost bone mineral density.
"It wouldn't be so bad if there simply was no obvious benefit," said Gary Schwartz, a prostate cancer epidemiologist at Wake Forest Baptist and lead author of the study.
"The problem is there is evidence that calcium supplements increase the risk of cardiovascular disease and aggressive prostate cancer, the very disease that we are trying to treat."
The researchers said further research is necessary to verify their findings, such as comparing a calcium and vitamin D supplement treated group with a non-supplemented group. The goal would be to review not only potential benefits â€" in bone mineral density and in the risk of fracture â€" but also the possible risks.
Part of the challenge of publishing research on dietary supplements and food safety is that when it comes to medical studies, consumer spending and corporate profits can be a combustible mix for scientists and researchers.
Dr. William Applegate, former dean of Wake Forest University School of Medicine, has said that "the higher the financial stake involved in a study, the greater the level of industry criticism tends to be generated."
The Natural Products Association, a trade group for dietary supplements, has been known to criticize studies and media reports that cast a shadow on the value and safety of supplements.
Cara Welch, the group's senior vice president of scientific and regulatory affairs, said the study's co-authors acknowledged it has not been tested "whether supplementation of men undergoing ADT with calcium and/or vitamin D results in a higher bone mineral density."
"How can they then imply that calcium and vitamin D supplementation is actually bad for this population?" Welch asked. "This is an irresponsible conclusion to make.
"Calcium and vitamin D supplements have many documented benefits, and if this study concludes anything, it's that research continues on the full benefits of these supplements."
Although Schwartz acknowledged that some groups may find the study controversial, he said the research has led to a determination "that sometimes it is what you do know that ain't so."
"The effects of calcium and vitamin D supplementation in men undergoing ADT have been tested by comparing bone mineral density before and after supplementation in the same men. The results of virtually all studies showed a loss of bone mineral density in men undergoing ADT despite consumption of supplemental calcium and vitamin D."
"Thus, we concluded the risk/benefit profile of supplementing men undergoing androgen deprivation with calcium and/or vitamin D requires greater scrutiny."
No comments:
Post a Comment