Vitamin D levels may affect how well osteoporosis drugs work on women with low bone density.
Bisphosphonate drugs commonly used to treat osteoporosis are seven times more likely to benefit a patient when the individual's blood levels of vitamin D are above recommended levels.
"Maintaining adequate vitamin D levels above those recently recommended by the Institute of Medicine is important for optimizing a standard therapy to osteoporosis: bisphosphonates," study coauthor Richard Bockman, MD, PhD, chief of the endocrine service at Hospital for Special Surgery and professor of medicine at Weill Cornell Medical College, both in New York City, told redOrbit.
The Institute of Medicine (IOM) released recommendations last November on vitamin D intake, reporting that most adults up to age 70 need 600 International Units (IU) a day to maintain bone health. Along with adequate calcium, this intake is enough to ensure adequate vitamin D levels in the blood, according to the IOM. Adequate levels were put at 20 nanograms per milliliter (ng/mL).
In Bockman's study, however, a 20-30 ng/mL was associated with a high likelihood of poor response to at least 18 months of bisphosphonate treatment. Patients with a blood level of 33 ng/Ml and above had a sevenfold greater likelihood of having a favorable response to the therapy.
"This value of at least 33 ng/mL is higher than the level considered as "adequate" by the Institute of Medicine report for the general population and most likely requires a vitamin D intake higher than 600IU for this therapeutic outcome," Bockman told redOrbit. "In the future, I think we're going to see vitamin D recommendations based on specific conditions."
