title: Vitamin D status in children with cystic fibrosis. Associations with inflammation and bacterial colonization.
abstract: BACKGROUND
  Patients with cystic fibrosis (CF) have high rates of vitamin D insufficiency. The relation between vitamin D status and inflammation in patients with CF is poorly understood.
  
  
  OBJECTIVE
  To determine the prevalence of vitamin D deficiency and insufficiency in a young CF population and to examine correlations between vitamin D status, disease severity, and inflammatory markers.
  
  
  METHODS
  This was a retrospective chart review of patients with CF under the age of 12 years. Serum laboratory parameters, growth indices, pancreatic status, CFTR genetics, medications, microbiology, and presence of CF-related comorbidities were collected for patients who had fat-soluble vitamin levels measured between January 1, 2009 and December 31, 2011. Vitamin D deficiency was defined as a serum 25(OH)D less than 20 ng/ml and insufficiency as serum 25(OH)D 20 to 29.9 ng/ml. Associations between serum vitamin D concentration and clinical/inflammatory markers were assessed using Chi-square and t tests.
  
  
  RESULTS
  Data were collected for 148 children. The mean serum 25(OH)D concentration was 32.4 ng/ml (SD, 8.9). Seven percent (10 of 148) were vitamin D deficient, and 36% (53 of 148) were vitamin D insufficient. Among the pancreatic-sufficient patients, 50% (14 of 28) were vitamin D insufficient/deficient, whereas among pancreatic-insufficient patients, 41% (49 of 120) were vitamin D insufficient/deficient. Pseudomonas aeruginosa was a more common pathogen in the patients who were vitamin D insufficient/deficient (18 of 63 vs. 11 of 85, P = 0.018). There was no difference between vitamin D-sufficient versus -insufficient groups in terms of other bacterial colonization or inflammatory markers.
  
  
  CONCLUSIONS
  Overall, vitamin D insufficiency is common among young children with CF. Vitamin D insufficiency is prevalent even in children who are pancreatic sufficient. In this population, vitamin D insufficiency is associated with a history of Pseudomonas colonization but not with classic markers of systemic inflammation.
authors.affiliation: 1 Children's Hospital Boston, Division of Respiratory Diseases, Harvard Medical School, Boston, Massachusetts.
authors.forename: Tregony
authors.initials: T
authors.lastname: Simoneau
authors.forename: Omar
authors.initials: O
authors.lastname: Bazzaz
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Sawicki
authors.forename: Catherine
authors.initials: C
authors.lastname: Gordon
mesh_terms: D002097:C-Reactive Protein / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000453:epidemiology* / Q000276:immunology; D010188:Exocrine Pancreatic Insufficiency / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007223:Infant; D007249:Inflammation / Q000276:immunology; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D015995:Prevalence; D011552:Pseudomonas Infections / Q000453:epidemiology*; D011550:Pseudomonas aeruginosa; D012141:Respiratory Tract Infections / Q000453:epidemiology*; D012189:Retrospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D007074:Immunoglobulin G; D014807:Vitamin D; D007073:Immunoglobulin E; D002097:C-Reactive Protein; C104450:25-hydroxyvitamin D