title: Spirometry in 5-year-olds--validation of current guidelines and the relation with asthma.
abstract: BACKGROUND
  Spirometry is more frequently measured in younger children. Our primary aim was to validate 2005 ATS-ERS Task Force standards for spirometry in adults and older children among a population of 5-year-old children. Our secondary aim was to relate spirometry to asthma symptoms.
  
  
  METHODS
  Children were participants in a longitudinal cohort study where asthma symptoms and spirometry were assessed.
  
  
  RESULTS
  Of the 827 children assessed, spirometry was obtained in 638 (85 with wheeze). A back-extrapolated volume/FVC ratio of <5% was achieved in 99% of children, the best two FVC were < or =150 ml of each other in 89% and three efforts were obtained within six attempts in 88%. The best two FVC were within 10% of each other in 82% of children. Only 13% achieved a forced expiratory time (FET) of > or =3 sec, whereas 80% had an FET of > or =1 sec. All criteria (including FET > or =1 s and FVC < or =10%) were met in 400 (65%) of the 638 children. Most spirometric indices were reduced in association with current wheeze and a history of asthma; children with current wheeze had a mean reduction of 0.65 FEV(1) z score compared to healthy children, P < 0.001. An FEV(1) z score of -1.0 had 82% sensitivity but only 50% specificity for current wheeze, the corresponding numbers for an FEF(50) z score of -1.0 being 79% and 71%.
  
  
  CONCLUSIONS
  The standards for spirometry are mostly achieved in this age group but are not necessarily valid and require revision. Reliable spirometry is feasible in 5-year-old children where reduced measurements are associated with asthma symptoms and in whom FEF(50) appears to be the most discriminatory variable.
authors.affiliation: Department of Child Health, University of Aberdeen, Aberdeen, UK. s.w.turner@abdn.ac.uk
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Turner
authors.forename: Leone C A
authors.initials: LC
authors.lastname: Craig
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Harbour
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Forbes
authors.forename: Geraldine
authors.initials: G
authors.lastname: McNeill
authors.forename: Anthony
authors.initials: A
authors.lastname: Seaton
authors.forename: Graham
authors.initials: G
authors.lastname: Devereux
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Helms
mesh_terms: D001249:Asthma / Q000175:diagnosis* / Q000503:physiopathology; D002675:Child, Preschool; D004867:Equipment Design; D005260:Female; D005540:Forced Expiratory Flow Rates / Q000502:physiology; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007223:Infant; D008297:Male; D017410:Practice Guidelines as Topic / Q000592:standards*; D015203:Reproducibility of Results; D012135:Respiratory Sounds / Q000503:physiopathology; D012720:Severity of Illness Index; D013147:Spirometry / Q000295:instrumentation / Q000592:standards / Q000639:trends*; D014797:Vital Capacity / Q000502:physiology