Higher Vit D levels improve osteoporosis drug responses:
Women In Transition Menopause
Endocrine Society
The Endocrine Society's 93rd Annual Meeting was the site of a presentation on June 6, 2011 of the finding of Richard Bockman, PhD and his associates at Hospital for Special Surgery of a better response to treatment with bisphosphonate drugs among women whose vitamin D levels were higher than the range of 20 to 30 nanograms per milliliter considered adequate by the Institute of Medicine (IOM).
The current study included 160 women with osteoporosis who had been using alendronate, residronate, ibandronate or zolendronate for 18 months or more and who had received two or more bone mineral density scans separated by 18 months to 5 years. Eighty-nine of the participants were classified as responders to bisphosphonates, and 71 were nonresponders, which included 42 women with low bone mineral density, 17 who experienced a fracture, and 12 having a persistently low T-score. "The way the data are expressed for a bone density is how many standard deviations are you away from the normal," Dr Bockman explained. "One standard deviation from the normal is a T score of one. Two standard deviations is a T score of two. Below the normal, it is a minus two and above the normal is a plus two. If your bone density is more than 2.5 standard deviations below the normal, that defines a low bone mass that is considered to be osteoporosis."
The researchers found that bisphosphonate responders were likelier than nonresponders to have a 25-hydroxyvitamin D level of 33 nanograms per milliliter or higher. Eighty-three percent of those whose vitamin D levels were lowest at less than 20 nanograms per milliliters were nonresponders to bisphosphonates, compared to 24.6 percent of those whose levels were highest at 40 nanograms per milliliter or more. "You are seven times more likely to respond to bisphosphonates if your 25-hydroxyvitamin D level is 33 nanograms/milliliter and above," stated Dr Bockman, who is a professor of medicine at Weill Cornell Medical College. "If you want to see a particular outcome from this treatment, then maybe 20 to 30 is not appropriate. When you see a seven times greater effect, that is pretty impressive."
"This value of at least 33 nanograms/milliliter 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 600 IU for this therapeutic outcome," he noted. "In the future, I think we're going to see vitamin D recommendations based on specific conditions."
"We selected 33 as the cutoff and subsequently showed that it was the right choice, with more being better," Dr Bockman added. "If you look at the medical literature, researchers talk perhaps about a 20 percent increase in response rate, occasionally a doubling, but when you see a sevenfold improvement in outcome, you have to be impressed that it is probably important."
The current study included 160 women with osteoporosis who had been using alendronate, residronate, ibandronate or zolendronate for 18 months or more and who had received two or more bone mineral density scans separated by 18 months to 5 years. Eighty-nine of the participants were classified as responders to bisphosphonates, and 71 were nonresponders, which included 42 women with low bone mineral density, 17 who experienced a fracture, and 12 having a persistently low T-score. "The way the data are expressed for a bone density is how many standard deviations are you away from the normal," Dr Bockman explained. "One standard deviation from the normal is a T score of one. Two standard deviations is a T score of two. Below the normal, it is a minus two and above the normal is a plus two. If your bone density is more than 2.5 standard deviations below the normal, that defines a low bone mass that is considered to be osteoporosis."
The researchers found that bisphosphonate responders were likelier than nonresponders to have a 25-hydroxyvitamin D level of 33 nanograms per milliliter or higher. Eighty-three percent of those whose vitamin D levels were lowest at less than 20 nanograms per milliliters were nonresponders to bisphosphonates, compared to 24.6 percent of those whose levels were highest at 40 nanograms per milliliter or more. "You are seven times more likely to respond to bisphosphonates if your 25-hydroxyvitamin D level is 33 nanograms/milliliter and above," stated Dr Bockman, who is a professor of medicine at Weill Cornell Medical College. "If you want to see a particular outcome from this treatment, then maybe 20 to 30 is not appropriate. When you see a seven times greater effect, that is pretty impressive."
"This value of at least 33 nanograms/milliliter 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 600 IU for this therapeutic outcome," he noted. "In the future, I think we're going to see vitamin D recommendations based on specific conditions."
"We selected 33 as the cutoff and subsequently showed that it was the right choice, with more being better," Dr Bockman added. "If you look at the medical literature, researchers talk perhaps about a 20 percent increase in response rate, occasionally a doubling, but when you see a sevenfold improvement in outcome, you have to be impressed that it is probably important."
