title: Timing of infant feeding in relation to childhood asthma and allergic diseases.
abstract: BACKGROUND
  Emerging evidence questions current recommendations on the timing of infant feeding for the prevention of childhood allergies. The evidence for asthma is inconclusive.
  
  
  OBJECTIVE
  We sought to investigate the associations between the duration of breast-feeding and timing of introduction of complementary foods and the development of asthma and allergies by the age of 5 years.
  
  
  METHODS
  Data were analyzed for 3781 consecutively born children. The dietary exposures were categorized into thirds and analyzed as time-dependent variables. Asthma, allergic rhinitis, and atopic eczema end points were assessed by using the International Study of Asthma and Allergies in Childhood questionnaire, whereas IgE antibodies were analyzed from serum samples at the age of 5 years. Cox proportional hazard and logistic regressions were used for the analyses.
  
  
  RESULTS
  The median duration of exclusive and total breast-feeding was 1.4 months (interquartile range, 0.2-3.5 months) and 7.0 months (interquartile range, 4.0-11.0 months), respectively. Total breast-feeding of 9.5 months or less was associated with an increased risk of nonatopic asthma. Introduction of wheat, rye, oats, or barley at 5 to 5.5 months was inversely associated with asthma and allergic rhinitis, whereas introduction of other cereals at less than 4.5 months increased the risk of atopic eczema. Introduction of egg at 11 months or less was inversely associated with asthma, allergic rhinitis, and atopic sensitization, whereas introduction of fish at 9 months or less was inversely associated with allergic rhinitis and atopic sensitization.
  
  
  CONCLUSIONS
  Early introduction of wheat, rye, oats, and barley cereals; fish; and egg (respective to the timing of introduction of each food) seems to decrease the risk of asthma, allergic rhinitis, and atopic sensitization in childhood. Longer duration of total breast-feeding, rather than its exclusivity, was protective against the development of nonatopic but not atopic asthma, suggesting a potential differing effect of breast-feeding on different asthma phenotypes.
authors.affiliation: School of Health Sciences, University of Tampere, Tampere, Finland. bright.nwaru@uta.fi
authors.forename: Bright I
authors.initials: BI
authors.lastname: Nwaru
authors.forename: Hanna-Mari
authors.initials: HM
authors.lastname: Takkinen
authors.forename: Onni
authors.initials: O
authors.lastname: Niemelä
authors.forename: Minna
authors.initials: M
authors.lastname: Kaila
authors.forename: Maijaliisa
authors.initials: M
authors.lastname: Erkkola
authors.forename: Suvi
authors.initials: S
authors.lastname: Ahonen
authors.forename: Anna-Maija
authors.initials: AM
authors.lastname: Haapala
authors.forename: Michael G
authors.initials: MG
authors.lastname: Kenward
authors.forename: Juha
authors.initials: J
authors.lastname: Pekkanen
authors.forename: Riitta
authors.initials: R
authors.lastname: Lahesmaa
authors.forename: Juha
authors.initials: J
authors.lastname: Kere
authors.forename: Olli
authors.initials: O
authors.lastname: Simell
authors.forename: Riitta
authors.initials: R
authors.lastname: Veijola
authors.forename: Jorma
authors.initials: J
authors.lastname: Ilonen
authors.forename: Heikki
authors.initials: H
authors.lastname: Hyöty
authors.forename: Mikael
authors.initials: M
authors.lastname: Knip
authors.forename: Suvi M
authors.initials: SM
authors.lastname: Virtanen
mesh_terms: D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D001942:Breast Feeding; D002675:Child, Preschool; D004032:Diet; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D011795:Surveys and Questionnaires; D013997:Time Factors