title: Prenatal vitamin d supplementation and child respiratory health: a randomised controlled trial.
abstract: BACKGROUND
  Observational studies suggest high prenatal vitamin D intake may be associated with reduced childhood wheezing. We examined the effect of prenatal vitamin D on childhood wheezing in an interventional study.
  
  
  METHODS
  We randomised 180 pregnant women at 27 weeks gestation to either no vitamin D, 800 IU ergocalciferol daily until delivery or single oral bolus of 200,000 IU cholecalciferol, in an ethnically stratified, randomised controlled trial. Supplementation improved but did not optimise vitamin D status. Researchers blind to allocation assessed offspring at 3 years. Primary outcome was any history of wheeze assessed by validated questionnaire. Secondary outcomes included atopy, respiratory infection, impulse oscillometry and exhaled nitric oxide. Primary analyses used logistic and linear regression.
  
  
  RESULTS
  We evaluated 158 of 180 (88%) offspring at age 3 years for the primary outcome. Atopy was assessed by skin test for 95 children (53%), serum IgE for 86 (48%), exhaled nitric oxide for 62 (34%) and impulse oscillometry of acceptable quality for 51 (28%). We found no difference between supplemented and control groups in risk of wheeze [no vitamin D: 14/50 (28%); any vitamin D: 26/108 (24%) (risk ratio 0.86; 95% confidence interval 0.49, 1.50; P = 0.69)]. There was no significant difference in atopy, eczema risk, lung function or exhaled nitric oxide between supplemented groups and controls.
  
  
  CONCLUSIONS
  Prenatal vitamin D supplementation in late pregnancy that had a modest effect on cord blood vitamin D level, was not associated with decreased wheezing in offspring at age three years.
  
  
  BACKGROUND
  Controlled-Trials.com ISRCTN68645785.
authors.affiliation: Department of Paediatrics, Imperial College London, London, United Kingdom.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Goldring
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Griffiths
authors.forename: Adrian R
authors.initials: AR
authors.lastname: Martineau
authors.forename: Stephen
authors.initials: S
authors.lastname: Robinson
authors.forename: Christina
authors.initials: C
authors.lastname: Yu
authors.forename: Sheree
authors.initials: S
authors.lastname: Poulton
authors.forename: Jane C
authors.initials: JC
authors.lastname: Kirkby
authors.forename: Janet
authors.initials: J
authors.lastname: Stocks
authors.forename: Richard
authors.initials: R
authors.lastname: Hooper
authors.forename: Seif O
authors.initials: SO
authors.lastname: Shaheen
authors.forename: John O
authors.initials: JO
authors.lastname: Warner
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Boyle
mesh_terms: D001944:Breath Tests; D002675:Child, Preschool; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000517:prevention & control*; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D009569:Nitric Oxide / Q000032:analysis; D011247:Pregnancy; D011295:Prenatal Care; D012135:Respiratory Sounds; D012141:Respiratory Tract Infections / Q000517:prevention & control*; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D014807:Vitamin D; D009569:Nitric Oxide; D007073:Immunoglobulin E