title: Cord blood 25(OH)-vitamin D deficiency and childhood asthma, allergy and eczema: the COPSAC2000 birth cohort study.
abstract: BACKGROUND
  Epidemiological studies have suggested an association between maternal vitamin D dietary intake during pregnancy and risk of asthma and allergy in the offspring. However, prospective clinical studies on vitamin D measured in cord blood and development of clinical end-points are sparse.
  
  
  OBJECTIVE
  To investigate the interdependence of cord blood 25-hydroxyvitamin D (25(OH)-Vitamin D) level and investigator-diagnosed asthma- and allergy-related conditions during preschool-age.
  
  
  METHODS
  Cord blood 25(OH)-Vitamin D level was measured in 257 children from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2000) at-risk mother-child cohort. Troublesome lung symptoms (TROLS), asthma, respiratory infections, allergic rhinitis, and eczema, at age 0-7 yrs were diagnosed exclusively by the COPSAC pediatricians strictly adhering to predefined algorithms. Objective assessments of lung function and sensitization were performed repeatedly from birth.
  
  
  RESULTS
  After adjusting for season of birth, deficient cord blood 25(OH)-Vitamin D level (<50 nmol/L) was associated with a 2.7-fold increased risk of recurrent TROLS (HR = 2.65; 95% CI = 1.02-6.86), but showed no association with respiratory infections or asthma. We saw no association between cord blood 25(OH)-Vitamin D level and lung function, sensitization, rhinitis or eczema. The effects were unaffected from adjusting for multiple lifestyle factors.
  
  
  CONCLUSIONS
  Cord blood 25(OH)-Vitamin D deficiency associated with increased risk of recurrent TROLS till age 7 years. Randomized controlled trials of vitamin D supplementation during pregnancy are needed to prove causality.
authors.affiliation: Copenhagen Prospective Studies on Asthma in Childhood, Health Sciences, University of Copenhagen, Danish Pediatric Asthma Center, Copenhagen University Hospital, Gentofte, Denmark.
authors.forename: Bo L
authors.initials: BL
authors.lastname: Chawes
authors.affiliation: Copenhagen Prospective Studies on Asthma in Childhood, Health Sciences, University of Copenhagen, Danish Pediatric Asthma Center, Copenhagen University Hospital, Gentofte, Denmark.
authors.forename: Klaus
authors.initials: K
authors.lastname: Bønnelykke
authors.affiliation: Copenhagen Prospective Studies on Asthma in Childhood, Health Sciences, University of Copenhagen, Danish Pediatric Asthma Center, Copenhagen University Hospital, Gentofte, Denmark.
authors.forename: Pia F
authors.initials: PF
authors.lastname: Jensen
authors.affiliation: Copenhagen Prospective Studies on Asthma in Childhood, Health Sciences, University of Copenhagen, Danish Pediatric Asthma Center, Copenhagen University Hospital, Gentofte, Denmark.
authors.forename: Ann-Marie M
authors.initials: AM
authors.lastname: Schoos
authors.affiliation: Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Lene
authors.initials: L
authors.lastname: Heickendorff
authors.affiliation: Copenhagen Prospective Studies on Asthma in Childhood, Health Sciences, University of Copenhagen, Danish Pediatric Asthma Center, Copenhagen University Hospital, Gentofte, Denmark.
authors.forename: Hans
authors.initials: H
authors.lastname: Bisgaard
mesh_terms: D000328:Adult; D017668:Age of Onset; D001249:Asthma / Q000097:blood / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D004485:Eczema / Q000097:blood / Q000453:epidemiology*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000453:epidemiology*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D