02/02/12

SAN DIEGO – Postmenopausal women who are being treated for low bone mineral density have nearly five- fold the response rate to bisphosphonate therapy if they maintain a serum vitamin D level of 33 ng/mL or higher than they do with a level below that threshold, according to a study reported at the annual meeting of the American Society for Bone and Mineral Research.

Moreover, a multivariate analysis demonstrated that for each 1-ng/mL decrease in serum vitamin D level, the likelihood of a favorable response to bisphosphonate therapy dropped by 5%, Dr. Amanda Carmel reported at the meeting.

The 33 ng/mL threshold is higher than recommended as adequate for the general population in the 2010 Institute of Medicine report. The discrepancy suggests that higher vitamin D levels may be required for specific therapeutic outcomes, said Dr. Carmel of Cornell University, New York.

The study was based on a chart review of 210 women (mean age 66 years) who had been on bisphosphonate therapy for low bone mass or osteoporosis for an average of 5 years.

Half were on alendronate (Fosamax), 27% were on risedronate (Actonel), and the rest were on ibandronate (Boniva) or zoledronic acid (Reclast).

Dr. Carmel reported having no financial conflict.


Bruce Jancin is with the Denver bureau of Elsevier Global Medical News.