title: Implications of reversibility testing on prevalence and risk factors for chronic obstructive pulmonary disease: a community study.
abstract: BACKGROUND
  The Global Initiative for Obstructive Lung Disease (GOLD) has defined chronic obstructive pulmonary disease (COPD) as a post-bronchodilator ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) of <0.7. In the first general population based study to apply post-bronchodilator values, the prevalence and predictors of GOLD defined COPD were assessed and the implications of beta2 agonist reversibility testing examined.
  
  
  METHODS
  Based on a random population sample, 2235 subjects (77%) aged 26-82 years performed spirometric tests before and 15 minutes after inhaling 0.3 mg salbutamol.
  
  
  RESULTS
  The prevalence of GOLD defined COPD was 7.0% (95% confidence interval (CI) 5.9 to 8.0). This estimate was 27% lower than COPD defined without bronchodilatation. One percent of the population had severe or very severe COPD. Compared with women, men had 3.1 (95% CI 2.1 to 4.8) times higher odds for COPD. Subjects with a smoking history of more than 20 pack years had an odds ratio (OR) of 6.2 (95% CI 3.4 to 11.0) for COPD relative to never-smokers, while subjects older than 75 years had an OR of 18.0 (95% CI 9.2 to 35.0) relative to those below 45 years. Subjects with primary education only had an OR of 2.8 (95% CI 1.4 to 5.3) compared with those with university education. Subjects with body mass index (BMI) <20 kg/m2 were more likely than subjects with BMI 25-29.9 kg/m2 to have COPD (OR 2.4, 95% CI 1.1 to 5.3). The adjusted proportion of COPD attributable to smoking was 68%.
  
  
  CONCLUSIONS
  These results indicate that community programmes on prevention of COPD should focus on anti-smoking, nutritional aspects, and socioeconomic conditions. The effect of beta2 reversibility testing on prevalence estimates of COPD was substantial.
authors.affiliation: Institute of Medicine, University of Bergen, N-5021 Bergen, Norway. ane.johannessen@helse-bergen.no
authors.forename: A
authors.initials: A
authors.lastname: Johannessen
authors.forename: E R
authors.initials: ER
authors.lastname: Omenaas
authors.forename: P S
authors.initials: PS
authors.lastname: Bakke
authors.forename: A
authors.initials: A
authors.lastname: Gulsvik
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001993:Bronchodilator Agents / Q000627:therapeutic use; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D012307:Risk Factors; D014797:Vital Capacity / Q000502:physiology
chemical_list: D001993:Bronchodilator Agents