title: Enterovirus infections in early childhood and the risk of atopic disease--a nested case-control study.
abstract: BACKGROUND
  Enterovirus infections in childhood have been associated with a reduced risk of atopy in cross-sectional studies.
  
  
  OBJECTIVE
  To study the relation between enterovirus infections in the first 2 years of life and atopic disease with IgE sensitization in a prospective study setting.
  
  
  METHODS
  This was a nested case-control study among children who had been followed from birth. Neutralizing antibodies against 12 enterovirus serotypes were analysed at the age of 2 years from 71 atopic children and 142 non-atopic control children. Atopy was defined as having an atopic disease and IgE antibodies against at least one aeroallergen by the age of 5 years.
  
  
  RESULTS
  Cumulative exposure to different enterovirus serotypes was inversely associated with atopy [odds ratio (OR) 0.73; 95% confidence interval (CI): 0.56-0.96]. The most pronounced protection was seen when echoviruses were analysed as a separate group (OR 0.63; 95%CI: 0.46-0.88).
  
  
  CONCLUSIONS
  We propose that exposure to several different enteroviruses in early childhood is inversely associated with atopic diseases. Our results support the hypothesis that repeated microbial infections in early life may protect from atopic sensitization and atopic diseases.
authors.affiliation: Department of Virology, School of Medicine, University of Tampere, Tampere, Finland. laura.m.korhonen@uta.fi
authors.forename: L
authors.initials: L
authors.lastname: Korhonen
authors.forename: A
authors.initials: A
authors.lastname: Kondrashova
authors.forename: S
authors.initials: S
authors.lastname: Tauriainen
authors.forename: A M
authors.initials: AM
authors.lastname: Haapala
authors.forename: H
authors.initials: H
authors.lastname: Huhtala
authors.forename: J
authors.initials: J
authors.lastname: Ilonen
authors.forename: O
authors.initials: O
authors.lastname: Simell
authors.forename: M
authors.initials: M
authors.lastname: Knip
authors.forename: M
authors.initials: M
authors.lastname: Lönnrot
authors.forename: H
authors.initials: H
authors.lastname: Hyöty
mesh_terms: D000367:Age Factors; D057134:Antibodies, Neutralizing / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D016022:Case-Control Studies; D002675:Child, Preschool; D004770:Enterovirus / Q000145:classification / Q000276:immunology; D004769:Enterovirus Infections / Q000150:complications* / Q000276:immunology; D005500:Follow-Up Studies; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000209:etiology*; D007223:Infant; D007231:Infant, Newborn; D012306:Risk; D016036:Seroepidemiologic Studies
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral