title: Day care attendance, recurrent respiratory tract infections and asthma.
abstract: OBJECTIVE
  Our objective was to use a causal model for childhood asthma to determine whether the effect of day care attendance on asthma was mediated by recurrent respiratory tract infections.
  
  
  METHODS
  A cross-sectional survey among 1447 children aged 6-16 years in Oslo. Their parents completed written questionnaires. A recursive logit model was used to estimate direct effects in terms of adjusted odds ratios (aOR).
  
  
  RESULTS
  Year of birth, number of siblings and length of maternal education were significantly associated with day care attendance. Attendance at day care increased the risk of early infections, aOR = 1.8 (1.3-2.5), and infections were associated with asthma, aOR = 4.9 (3.4-7.3). The crude association between day care and asthma was cOR = 1.5 (1.0-2.2), whereas the estimated direct effect was small and nonsignificant, aOR = 1.2 (0.8-1.9). The results may be influenced by overreporting of infections among parents of children with asthma.
  
  
  CONCLUSIONS
  Our results suggest that children who attend day care have an increased risk of asthma with early infections as a mediator of risk.
authors.affiliation: Section of Epidemiology, Department of Population Health Sciences, National Institute of Public Health, Oslo, Norway. wenche.nystad@folkehelsa.no
authors.forename: W
authors.initials: W
authors.lastname: Nystad
authors.forename: A
authors.initials: A
authors.lastname: Skrondal
authors.forename: P
authors.initials: P
authors.lastname: Magnus
mesh_terms: D000041:Absenteeism; D000293:Adolescent; D017677:Age Distribution; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D002656:Child Day Care Centers / Q000706:statistics & numerical data*; D002675:Child, Preschool; D015897:Comorbidity; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D012008:Recurrence; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000453:epidemiology*; D018570:Risk Assessment; D012307:Risk Factors; D017678:Sex Distribution