Vitamin D insufficiency in children, adolescents, and young adults with cystic fibrosis despite routine oral supplementation.
BACKGROUND
Cystic fibrosis (CF) with pancreatic insufficiency is associated with poor absorption of fat and fat-soluble vitamins, including vitamin D. Pancreatic enzyme supplementation does not completely correct fat malabsorption in CF patients.


OBJECTIVE
The objective of the study was to compare the vitamin D status of children, adolescents, and young adults with CF who were treated with routine vitamin D and pancreatic enzyme supplements with the vitamin D status of a healthy reference group from a similar geographic area.


METHODS
Growth, dietary intake, and serum concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], and parathyroid hormone (PTH) were measured in 101 white subjects with CF and a reference group of 177 white subjects.


RESULTS
The median daily vitamin D supplementation in the CF group was 800 IU. The mean +/- SD serum concentrations of 25(OH)D were 20.7 +/- 6.5 ng/mL in the CF group and 26.2 +/- 8.6 ng/mL in the reference group (P < 0.001). Vitamin D deficiency and insufficiency were defined as 25(OH)D concentrations < 11 ng/mL and < 30 ng/mL, respectively. Seven percent of the CF group and 2% of the healthy reference group were vitamin D deficient (P < 0.03). Ninety percent of the CF group and 74% of the healthy reference group were vitamin D insufficient (P < 0.01). Twenty-five percent of the CF group and 9% of the healthy reference group had elevated PTH (P < 0.006). The odds of vitamin D insufficiency in the CF group, compared with the healthy reference group, were 1.2 (95% CI: 1.1, 1.3) after adjustment for season and age.


CONCLUSIONS
Despite daily vitamin D supplementation, serum 25(OH)D concentrations remain low in children, adolescents, and young adults with CF.
Rovner
Alisha J
AJ
Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Stallings
Virginia A
VA
Schall
Joan I
JI
Leonard
Mary B
MB
Zemel
Babette S
BS
D000293:Adolescent; D000328:Adult; D002648:Child; D003550:Cystic Fibrosis / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000378:metabolism*; D010188:Exocrine Pancreatic Insufficiency / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D012621:Seasons; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000378:metabolism*
C470125:PTH protein, human; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D