Vitamin D levels should be higher in people taking certain osteoporosis drugs, experts say

Vitamin D works with calcium to strengthen bones. But adequate levels of vitamin D in the bloodstream also appear to boost the power of bisphosphonates, medications used to treat osteoporosis, according to research presented Monday.

The study adds to the evidence that the current recommendations for vitamin D may be too low. Late last year, the Institute of Medicine issued a report that declined to make changes to the recommendation -- despite many new studies supporting the need for more vitamin D than is typically consumed.

In the new study, presented at the annual meeting of the Endocrine Society, researchers found that having a circulating vitamin D level greater than 33 nanograms per milliliter was linked to a seven times greater likelihood of having a good response to bisphosphonates.

Bisphosphonates include medications such as Fosamax, Boniva and Actonel. The standard vitamin D blood test measures a component called 25-hydroxy vitamin D.

According to the IOM report, levels of 20 ng/ml to 30 ng/ml are adequate for most normal, healthy adults.

However, in the study, 83% of people with vitamin D levels less than 20 ng/ml had a poor response to bisphosphonates compared with 77% of people with levels between 20 ng/ml and 30 ng/ml, 42% of people with levels of 30 ng/ml to 40 ng/ml and 24% of those exceeding 40 ng/ml.

“There has been a lot of controversy over the correct vitamin D levels for people to have,” said the lead author of the study, Dr. Richard Bockman, chief of the endocrine service at Hospital for Special Surgery in New York, in a news release. “Vitamin D status should be optimized to improve outcomes in patients taking bisphosphonates.”

Related: Vitamin D levels are adequate in most Americans, survey finds

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