title: Prevalence of airways obstruction in a general population: European Respiratory Society vs American Thoracic Society definition.
abstract: OBJECTIVE
  To evaluate the distribution of airways obstruction in a general population sample.
  
  
  METHODS
  Cross-sectional epidemiologic survey of a general population sample living in Po Delta area (North Italy). Data on respiratory symptoms, diseases, and risk factors were collected through standardized interviewer-administered questionnaires. Lung function tests were performed, with criteria for defining airways obstruction based on the 1995 European Respiratory Society (ERS) statement (FEV(1)/vital capacity ratio < 88% predicted and < 89% predicted in men and women, respectively), "clinical" criteria (FEV(1)/FVC ratio < 70%), and the 1986 American Thoracic Society (ATS) statement (FEV(1)/FVC ratio < 75%).
  
  
  RESULTS
  A total of 1,727 subjects aged > 25 years investigated from 1988 to 1991 were included. Prevalence rates of airways obstruction for subjects 25 to 45 years old and subjects >/= 46 years old were as follows: ERS, 10.8% and 12.2%; clinical, 9.9% and 28.8%; and ATS, 27% and 57%, respectively. When considering only moderate/severe obstruction, the rates were as follows: ERS, 0.4% and 3.6%; clinical, 0.3% and 4.4%; and ATS, 0.5% and 5.2%, respectively. The trend was confirmed after stratifying for smoking habit and the presence/absence of respiratory symptoms/diseases. The highest specificity and predictive value for any respiratory symptom/disease was shown by the ERS, and the lowest was shown by the ATS criterion, while the reverse was true for sensitivity; overall accuracy was slightly lower for the ATS criterion. Multiple logistic regression models indicated a higher number of significant associations with known risk factors for airways obstruction according to clinical and ATS criteria than ERS criterion.
  
  
  CONCLUSIONS
  The prevalence of COPD in a general population depends very much on the criterion used for definition of airways obstruction. Further research is needed to reach a standardized and epidemiologically consistent criterion for airways obstruction.
authors.affiliation: CNR Institute of Clinical Physiology, Pulmonary Environmental Epidemiology Group Pisa, Italy. viegig@ifc.pi.cnr.it
authors.forename: G
authors.initials: G
authors.lastname: Viegi
authors.forename: M
authors.initials: M
authors.lastname: Pedreschi
authors.forename: F
authors.initials: F
authors.lastname: Pistelli
authors.forename: F
authors.initials: F
authors.lastname: Di Pede
authors.forename: S
authors.initials: S
authors.lastname: Baldacci
authors.forename: L
authors.initials: L
authors.lastname: Carrozzi
authors.forename: C
authors.initials: C
authors.lastname: Giuntini
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007391:International Cooperation; D007558:Italy / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011237:Predictive Value of Tests; D015995:Prevalence; D015272:Pulmonary Medicine; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012955:Societies, Medical; D014481:United States / Q000453:epidemiology; D014797:Vital Capacity