Vitamin D Repletion Regimen For Cystic Fibrosis Patients Did Not Work

Main Category: Cystic Fibrosis
Article Date: 15 Jul 2005 - 18:00 PDT

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The recently published vitamin D repletion regimen suggested by the Cystic Fibrosis Foundation's Consensus Panel on Bone Health for replacing the vitamin in cystic fibrosis (CF) patients has been called by researchers who tested it "strikingly ineffective." Out of 66 adults with CF, only 5 patients who had been treated with 50,000 international units of the vitamin per week for eight weeks had their serum levels corrected to the recommended degree.

The study was designed to determine the percentage of adults with CF who required the recommended vitamin D. repletion therapy because of serum levels below 30 nanograms per milliliter (30 ng/ml); to evaluate for the first time the effectiveness of a stepped up repletion protocol for CF patients; and to provide CF-specific data to assist in future optimal dosing.

Cystic fibrosis is a life-shortening inherited disorder that affects 30,000 persons in the U.S. Patients who are born with this problem produce abnormally thick and sticky mucus that often obstructs the lungs, leading to lung infections, as well as to the clogging of the pancreatic ducts which can prevent normal digestion. However, treatment for the disorder has improved greatly and predicted survival rates have increased from an average age of 25 in 1985 to over age 33 in 2005.

Since there has been an increase in survival, researchers have also been considering other health issues unique to the adult CF population. One issue is bone health because studies of bone density have determined that despite a young age, approximately 20 to 25 percent of adults with CF have osteoporosis and another 40 percent have osteopenia.

(Osteopenia is low bone volume due to inadequate replacement of bone loss from normal disintegration. Osteoporosis is abnormal loss of bone tissue, causing fragile bones that fracture easily.)

A adequate supply of vitamin D is needed for the body to absorb calcium from food and incorporate it into bone. A deficiency of vitamin D leads to abnormal bone growth and repair.

Of the 134 adults with CF in this study, 109 (81.3 percent) were found to have vitamin D levels below the recommended 30 ng/ml.

Of the 49 patients who started the second eight-week repletion test comprising a total of 800,000 international units of vitamin D, 33 completed the full course, but none corrected their vitamin D deficiency.

The authors noted that further research is required to determine the optimal level of vitamin D needed in order for CF patients to maximize calcium absorption and maintain bone health.

The research article appears in the second issue for July 2005 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.

For the complete text of these articles, please see the American Thoracic Society Online Web Site at atsjournals.org. For either contact information or to request a complimentary journalist subscription to ATS journals online, or if you would like to add your name to the Society's twice monthly journal news e-mail list, contact Cathy Carlomagno at 212-315-6442, or at ccarlomagno@thoracic.org.

Cathy Carlomagno
ccarlomagno@thoracic.org
212-315-6442
American Thoracic Society
American Thoracic Society Journal news tips for July 2005 (second issue)
www.thoracic.org

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