Existing recommendations for treating vitamin D deficiency in children with cystic fibrosis (CF) are too low to cover the serious need, leaving most at high risk for bone loss and rickets, according to researchers at Johns Hopkins Children's Center.
In results of their investigation, published in the October issue of The Journal of Pediatrics, the Johns Hopkins team found that nearly half of the 262 children with CF in the study were vitamin D deficient, and the majority of these remained persistently so, despite getting restorative doses equal to or higher than the recommendations set by the Cystic Fibrosis Foundation.
As a result of the findings, Hopkins already has amended its treatment protocol and now treats both adult and pediatric CF patients who have vitamin D deficiency with 50,000 IU daily for four weeks. Growing children with CF are especially vulnerable to vitamin D deficiency because a hallmark of their condition is poor absorption of nutrients and malnutrition. CF, a genetic disorder, is marked by the body's inability to transport chloride in and out of cells, causing mild to life-threatening complications, including recurrent and severe lung infections and delayed growth.
The Cystic Fibrosis Foundation defines vitamin D deficiency in patients as levels lower than 30 nanograms per milliliter and recommends that patients who are vitamin D deficient receive a weekly dose of 50,000 IU of ergocalciferol, a form of vitamin D.
"These findings are a big wake-up call not only because they show that many children with CF are lacking vitamin D, but also because the deficiency persists even in those children who are treated with weekly doses twice or three times as high as the current recommendations," says Hopkins Children's lung specialist Deanna Green, M.D., who led the research. "Clearly there is an urgent need to find more effective ways to restore healthy vitamin D levels."
In the meantime, investigators say, doctors caring for patients with CF should think about increasing the vitamin D intake beyond the current recommendations in those who are vitamin D deficient. They should also check vitamin D levels at least once a year in all CF patients and more frequently in those with abnormally low levels.
In the current study of CF patients treated at Hopkins Children's between 2003 and 2006, investigators found that 86 percent were vitamin D deficient in 2003, 50 percent were deficient in 2004, 54 percent were deficient in 2005, and 46 percent were deficient in 2006.
Comparing different weekly intakes of ergocalciferol, the Hopkins team found that the currently recommended 50,000 IU per week for eight weeks was effective in only 33 percent of the patients with vitamin D deficiency, while increasing the therapy to twice a week was effective in 26 percent of patients. Delivering the same dose three times a week corrected the deficiency in just 43 percent of children.