title: Birthweight and the risk of atopic diseases: the ISAAC Phase III study.
abstract: BACKGROUND
  The association between birthweight and asthma, eczema and rhinoconjunctivitisis conflicting.
  
  
  OBJECTIVE
  To examine the association between birthweight and symptoms of asthma, eczema and rhinoconjunctivitis.
  
  
  METHODS
  Parents or guardians of children aged 6–7 yr completed written questionnaires about symptoms of asthma, rhinoconjunctivitis and eczema, and several risk factors, including birthweight.
  
  
  RESULTS
  There were 162,324 children from 60 centres in 26 countries. Low birthweight(<2.5 kg) was associated with an increased risk of symptoms of asthma (current wheeze odds ratio = 1.20; 95% confidence interval = 1.12–1.30). Low birthweight was associated with a lower risk of eczema ever. Low birthweight was not associated with rhinoconjunctivitis. Large babies (birthweight ≥4.5 kg) were not associated with any of these outcomes.
  
  
  CONCLUSIONS
  This study has confirmed that low birthweight is a risk factor for symptoms of asthma, but not for rhinoconjunctivitis. The findings for eczema are equivocal.
authors.forename: Edwin A
authors.initials: EA
authors.lastname: Mitchell
authors.forename: Tadd
authors.initials: T
authors.lastname: Clayton
authors.forename: Luis
authors.initials: L
authors.lastname: García-Marcos
authors.forename: Neil
authors.initials: N
authors.lastname: Pearce
authors.forename: Sunia
authors.initials: S
authors.lastname: Foliaki
authors.forename: Gary
authors.initials: G
authors.lastname: Wong
mesh_terms: D001249:Asthma / Q000209:etiology*; D001724:Birth Weight; D002648:Child; D003233:Conjunctivitis, Allergic / Q000209:etiology*; D004485:Eczema / Q000209:etiology*; D006801:Humans; D065631:Rhinitis, Allergic / Q000209:etiology*; D012306:Risk