title: Validation of the Finnish ISAAC questionnaire on asthma against anti-asthmatic medication reimbursement database in 5-year-old children.
abstract: BACKGROUND
  Valid identification of childhood asthma at the population level for epidemiological purposes remains a challenge. We aimed at validating the Finnish version of the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire based on parental-reported childhood asthma.
  
  
  METHODS
  The ISAAC questionnaire has been validated against anti-asthmatic medication reimbursement data of the Finnish Social Insurance Institution, being the gold standard, among 2236 5-year-old consecutively born children (1996-2004) carrying human leukocyte antigen (HLA)-conferred susceptibility to type 1 diabetes. Two combined questionnaire questions (any wheezing symptom or use of asthma medication during the preceding 12 months plus ever asthma; any wheezing symptom or use of asthma medication during the preceding 12 months plus ever doctor-diagnosed asthma) were validated against valid reimbursement with purchase of at least one anti-asthmatic medication during a 12-month period. The validity of the questionnaire was estimated as the sensitivity, specificity, positive predictive value, negative predictive value, and Youden's index.
  
  
  RESULTS
  The sensitivity 0.98 [95% confidence interval (CI) = 0.92-0.99]; specificity 0.98 (95% CI = 0.97-0.98); negative predictive value 1.00 (95% CI = 1.00-1.00); and Youden's index 0.96 (95% CI = 0.96-0.96) were the same for each of the two sets of combined questions. The positive predictive value for the first combined question was 0.63 (95% CI = 0.55-0.71), while it was 0.64 (95% CI = 0.57-0.72) for the second combined question.
  
  
  CONCLUSIONS
  The Finnish ISAAC questionnaire was highly valid and is an acceptable instrument for the survey of the prevalence of parental-reported childhood asthma for epidemiological purposes.
authors.affiliation: Tampere School of Public Health, University of Tampere, Finland. bright.nwaru@uta.fi
authors.forename: Bright Ibeabughichi
authors.initials: BI
authors.lastname: Nwaru
authors.forename: Mirka
authors.initials: M
authors.lastname: Lumia
authors.forename: Minna
authors.initials: M
authors.lastname: Kaila
authors.forename: Päivi
authors.initials: P
authors.lastname: Luukkainen
authors.forename: Heli
authors.initials: H
authors.lastname: Tapanainen
authors.forename: Maijaliisa
authors.initials: M
authors.lastname: Erkkola
authors.forename: Suvi
authors.initials: S
authors.lastname: Ahonen
authors.forename: Juha
authors.initials: J
authors.lastname: Pekkanen
authors.forename: Timo
authors.initials: T
authors.lastname: Klaukka
authors.forename: Riitta
authors.initials: R
authors.lastname: Veijola
authors.forename: Olli
authors.initials: O
authors.lastname: Simell
authors.forename: Mikael
authors.initials: M
authors.lastname: Knip
authors.forename: Suvi Mirjami
authors.initials: SM
authors.lastname: Virtanen
mesh_terms: D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D002675:Child, Preschool; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007349:Insurance, Health, Reimbursement / Q000706:statistics & numerical data*; D008297:Male; D015995:Prevalence; D011795:Surveys and Questionnaires
chemical_list: D018927:Anti-Asthmatic Agents