title: Prevalence, severity and determinants of asthma in Danish five-year-olds.
abstract: BACKGROUND
  The prevalence of asthma and wheeze is increasing.
  
  
  OBJECTIVE
  To study the annual and cumulative prevalence of asthma and wheeze in 5-y-old Danish children.
  
  
  METHODS
  We obtained data on 3052 (82.0% of eligible) Danish children by a postal parental questionnaire including ISAAC questions regarding respiratory symptoms and our own questions on sociodemography and tobacco exposure.
  
  
  RESULTS
  "Wheeze ever" was reported in 38.3%, "doctor-diagnosed asthma ever" in 10.5%, "childhood bronchitis ever" in 30.0%, "current wheeze" (<12 mo) in 19.7%, and being "severe" (>3 episodes) in 3.9% of the children. Current wheeze was associated with male gender (OR 1.63, 95% CI 1.35-1.96), low parental post-primary education (OR 1.29, 95% CI 1.02-1.63 for <3 y vs > or =3 y) and current maternal smoking (OR 1.69, 95% CI 1.39-2.04). "Severe current wheeze" was recognized as asthma in six and childhood bronchitis in three of 10 cases. Nearly all diagnosed asthmatics had suffered wheeze, two-thirds recently.
  
  
  CONCLUSIONS
  We found a high prevalence of asthma and wheeze in Danish late-preschool children, associated with male gender, current maternal tobacco smoking and low parental post-primary education. The majority of children with current wheeze had an early onset, and severe early symptoms tended to persist. Used with consideration, the label "childhood bronchitis" seems purposeful.
authors.affiliation: Research Unit and Department for General Practice, University of Copenhagen, Copenhagen, Denmark. c.hermann@dadlnet.dk
authors.forename: Christian
authors.initials: C
authors.lastname: Hermann
authors.forename: Niels
authors.initials: N
authors.lastname: De Fine Olivarius
authors.forename: Arne
authors.initials: A
authors.lastname: Høst
authors.forename: Kamilla
authors.initials: K
authors.lastname: Begtrup
authors.forename: Hanne
authors.initials: H
authors.lastname: Hollnagel
mesh_terms: D001249:Asthma / Q000453:epidemiology*; D001991:Bronchitis / Q000453:epidemiology; D002675:Child, Preschool; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D015995:Prevalence; D012135:Respiratory Sounds; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology