MONDAY, Oct. 13 (HealthDay News) -- Existing guidelines for treating vitamin D deficiency in children with cystic fibrosis are too low and put patients at high risk for bone loss and rickets, a new study says.

Researchers from Johns Hopkins Children's Center looked at 262 children with cystic fibrosis (CF). Nearly half the children were vitamin D-deficient, and most of them remained persistently deficient, despite receiving restorative vitamin D doses equal to or higher than the Cystic Fibrosis Foundation-recommended 50,000 IU of ergocalciferol (a form of vitamin D) per week.

The study was published in the October issue of The Journal of Pediatrics.

CF is a genetic disorder in which the body is unable to transport chloride in and out of cells. This causes mild to life-threatening complications such as recurrent and severe lung infections and delayed growth. Because CF results in poor absorption of nutrients and malnutrition, growing children with CF are especially prone to vitamin D deficiency, according to background information in a Hopkins news release.

"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," study leader and lung specialist Dr. Deanna Green said in the news release.

"Clearly there is an urgent need to find more effective ways to restore healthy vitamin D levels," she added.

Until that happens, doctors should consider increasing vitamin D intake beyond the current recommendations in CF patients who are vitamin D deficient, Green and colleagues suggested. Doctors should also check vitamin D levels at least once a year in all CF patients and more frequently in patients with abnormally low vitamin D levels.

As a result of the findings, Hopkins amended its treatment protocol and now treats adult and child CF patients who have vitamin D deficiency with 50,000 IU of vitamin D daily for four weeks.

More information

The March of Dimes has more about cystic fibrosis.