title: Early childhood infectious diseases and the development of asthma up to school age: a birth cohort study.
abstract: OBJECTIVE
  To investigate the association between early childhood infections and subsequent development of asthma.
  
  
  METHODS
  Longitudinal birth cohort study.
  
  
  METHODS
  Five children's hospitals in five German cities.
  
  
  METHODS
  1314 children born in 1990 followed from birth to the age of 7 years.
  
  
  METHODS
  Asthma and asthmatic symptoms assessed longitudinally by parental questionnaires; atopic sensitisation assessed longitudinally by determination of IgE concentrations to various allergens; bronchial hyperreactivity assessed by bronchial histamine challenge at age 7 years.
  
  
  RESULTS
  Compared with children with </=1 episode of runny nose before the age of 1 year, those with >/=2 episodes were less likely to have a doctor's diagnosis of asthma at 7 years old (odds ratio 0.52 (95% confidence interval 0.29 to 0.92)) or to have wheeze at 7 years old (0.60 (0.38 to 0.94)), and were less likely to be atopic before the age of 5 years. Similarly, having >/=1 viral infection of the herpes type in the first 3 years of life was inversely associated with asthma at age 7 (odds ratio 0.48 (0.26 to 0.89)). Repeated lower respiratory tract infections in the first 3 years of life showed a positive association with wheeze up to the age of 7 years (odds ratio 3.37 (1.92 to 5.92) for >/=4 infections v </=3 infections).
  
  
  CONCLUSIONS
  Repeated viral infections other than lower respiratory tract infections early in life may reduce the risk of developing asthma up to school age.
authors.affiliation: Department of Pulmonology and Allergology, University Children's Hospital, Lindwurmstrasse 4, 80337 Munich, Germany. sabina.illi@kk-i.med.uni-muenchen.de
authors.forename: S
authors.initials: S
authors.lastname: Illi
authors.forename: E
authors.initials: E
authors.lastname: von Mutius
authors.forename: S
authors.initials: S
authors.lastname: Lau
authors.forename: R
authors.initials: R
authors.lastname: Bergmann
authors.forename: B
authors.initials: B
authors.lastname: Niggemann
authors.forename: C
authors.initials: C
authors.lastname: Sommerfeld
authors.forename: U
authors.initials: U
authors.lastname: Wahn
mesh_terms: D000906:Antibodies / Q000097:blood; D001249:Asthma / Q000209:etiology* / Q000276:immunology; D016535:Bronchial Hyperreactivity; D001985:Bronchial Provocation Tests; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003139:Common Cold / Q000150:complications*; D006566:Herpesviridae Infections / Q000150:complications*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D016013:Likelihood Functions; D016015:Logistic Models; D008137:Longitudinal Studies; D016017:Odds Ratio; D015995:Prevalence; D012008:Recurrence; D012135:Respiratory Sounds; D012141:Respiratory Tract Infections / Q000150:complications*
chemical_list: D000906:Antibodies; D007073:Immunoglobulin E