title: Efficacy of high-dose vitamin D in pediatric asthma: a systematic review and meta-analysis.
abstract: BACKGROUND
  Observational studies have suggested a relationship between vitamin D status and asthma-related respiratory outcomes. The benefit of vitamin D supplementation for pulmonary function, symptoms and exacerbations is not well established.
  
  
  OBJECTIVE
  To systematically review paediatric clinical trials investigating the role of vitamin D on asthma-related respiratory outcomes.
  
  
  METHODS
  MEDLINE, EMBASE and CENTRAL were searched until January 2014. No date or language restrictions.
  
  
  METHODS
  Clinical trials reporting asthma-related respiratory outcomes following vitamin D administration at a dose equal or greater than 500 IU per day were included and reviewed independently by two authors for full systematic review eligibility.
  
  
  METHODS
  Two reviewers independently extracted and verified pre-defined data fields.
  
  
  RESULTS
  We identified five studies that met study eligibility and assessed final data synthesis. The median trial size was 48 participants (range 17-430) and the average daily dose of cholecalciferol ranged from 500 to 2000 IU/day. Overall study methodological quality was high, but some heterogeneity in population and vitamin D dosing regimen was evident. Meta-analysis suggested a statistically significant reduction (RR 0.41, CI 0.27-0.63) in asthma exacerbation with vitamin D therapy.
  
  
  CONCLUSIONS
  Due to variability in outcome selection and missing data, it was not possible to perform meta-analysis for pulmonary function testing and asthma symptom scores. Vitamin D-related adverse events were not considered in four of five papers.
  
  
  CONCLUSIONS
  Available evidence from this systematic review suggests that high dose vitamin D may prevent asthma exacerbation. This should be confirmed through larger well-designed randomised controlled trials.
authors.affiliation: Division of Critical Care, Department of Pediatrics, Faculty of Medicine, University of Ottawa, Children's Hospital of Eastern Ontario , Ottawa , Canada .
authors.forename: Supichaya
authors.initials: S
authors.lastname: Pojsupap
authors.forename: Klevis
authors.initials: K
authors.lastname: Iliriani
authors.forename: Tatiana Zorub Assis Loreto
authors.initials: TZ
authors.lastname: Sampaio
authors.forename: Katie
authors.initials: K
authors.lastname: O'Hearn
authors.forename: Thomas
authors.initials: T
authors.lastname: Kovesi
authors.forename: Kusum
authors.initials: K
authors.lastname: Menon
authors.forename: James Dayre
authors.initials: JD
authors.lastname: McNally
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D012129:Respiratory Function Tests; D014807:Vitamin D / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D014807:Vitamin D
keywords: Asthma; Vitamin D; asthma-related respiratory outcomes; children; systematic review