title: Serum vitamin D levels in children with cystic fibrosis.
abstract: Osteopenia is increasingly recognized in adults with cystic fibrosis (CF), and is potentially related to vitamin D deficiency in both adulthood and childhood. Vitamin D supplements are recommended and prescribed to all pancreatic-insufficient patients. We aimed to ascertain whether vitamin D deficiency in children with CF was prevalent. 25-hydroxyvitamin D (25-OHD) was measured in 290 children attending a specialist pediatric CF clinic for annual assessment. 25-OHD levels were compared with reference values and to other biochemical markers, lung function, and growth. Levels were also analyzed by pancreatic status and by the presence of CF-related liver disease. Median 25-OHD was 65 (range, 9-190) nmol/l. One percent had levels below 15 nmol/l, and 6% had levels less than 25 nmol/l. Levels were lower in adolescents (P < 0.001) and during the "winter" months (P < 0.001). No relationship was found with pancreatic status or liver disease. In conclusion, the majority of children had normal 25-OHD levels. Interpretation is difficult due to a lack of knowledge of optimal levels of 25-OHD required for healthy bone accretion. Lower levels in adolescents may be a precursor to low levels in adulthood, and did not seem to be simply related to poor compliance with supplementation. This may reflect normal physiology.
authors.affiliation: Department of Paediatrics, Royal Brompton Hospital, London, UK. richard.chavasse@epsom-sthelier.nhs.uk
authors.forename: R J
authors.initials: RJ
authors.lastname: Chavasse
authors.forename: J
authors.initials: J
authors.lastname: Francis
authors.forename: I
authors.initials: I
authors.lastname: Balfour-Lynn
authors.forename: M
authors.initials: M
authors.lastname: Rosenthal
authors.forename: A
authors.initials: A
authors.lastname: Bush
mesh_terms: D000293:Adolescent; D000328:Adult; D001851:Bone Diseases, Metabolic / Q000209:etiology / Q000517:prevention & control; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000097:blood* / Q000150:complications; D010188:Exocrine Pancreatic Insufficiency / Q000150:complications / Q000209:etiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood*; D014808:Vitamin D Deficiency / Q000150:complications / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D