title: Lower respiratory tract infections among Norwegian infants with siblings in day care.
abstract: OBJECTIVE
  The purpose of this study was to assess the role of siblings in day care as a determinant of infants' risk of lower respiratory tract infections.
  
  
  METHODS
  A total of 3238 children (86%) out of 3754 Oslo, Norway, newborns recruited in 1992/93 were followed for 1 year.
  
  
  RESULTS
  In logistic regression analysis, the risk of infection was increased in (1) infants with one or more siblings compared with infants without siblings (adjusted odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.84, 2.85) and (2) infants with one or more siblings in day care compared with infants with siblings not in day care (adjusted OR = 1.7; 95% CI = 1.21, 2.26).
  
  
  CONCLUSIONS
  The results suggest that siblings in day care outside the home increase infants' risk of lower respiratory tract infections.
authors.affiliation: Department of Public Health, University of Helsinki, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Nafstad
authors.forename: J A
authors.initials: JA
authors.lastname: Hagen
authors.forename: G
authors.initials: G
authors.lastname: Botten
authors.forename: J J
authors.initials: JJ
authors.lastname: Jaakkola
mesh_terms: D015331:Cohort Studies; D003631:Day Care, Medical; D004781:Environmental Exposure; D005192:Family Health; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D009664:Norway / Q000453:epidemiology; D009679:Nuclear Family; D015203:Reproducibility of Results; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000209:etiology*