title: Evaluation of the global lung function initiative 2012 reference values for spirometry in a Swedish population sample.
abstract: BACKGROUND
  The Global Lung Function Initiative 2012 (GLI) reference values are currently endorsed by several respiratory societies but evaluations of applicability for adults resident in European countries are lacking. The aim of this study was to evaluate if the GLI reference values are appropriate for an adult Caucasian Swedish population.
  
  
  METHODS
  During 2008-2013, clinical examinations including spirometry were performed on general population samples in northern Sweden, in which 501 healthy Caucasian non-smokers were identified. Predicted GLI reference values and Z-scores were calculated for each healthy non-smoking subject and the distributions and mean values for FEV1, FVC and the FEV1/FVC ratio were examined. The prevalence of airway obstruction among these healthy non-smokers was calculated based on the Lower Limit of normal (LLN) criterion (lower fifth percentile) for the FEV1/FVC ratio. Thus, by definition, a prevalence of 5% was expected.
  
  
  RESULTS
  The Z-scores for FEV1, FVC and FEV1/FVC were reasonably, although not perfectly, normally distributed, but not centred on zero. Both predicted FEV1 and, in particular, FVC were lower compared to the observed values in the sample. The deviations were greater among women compared to men. The prevalence of airway obstruction based on the LLN criterion for the FEV1/FVC ratio was 9.4% among women and 2.7% among men.
  
  
  CONCLUSIONS
  The use of the GLI reference values may produce biased prevalence estimates of airway obstruction in Sweden, especially among women. These results demonstrate the importance of validating the GLI reference values in different countries.
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine, the OLIN unit, Umeå university, Umeå, Sweden. helena.backman@nll.se.
authors.forename: Helena
authors.initials: H
authors.lastname: Backman
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Medicine, the OLIN unit, Umeå University, Umeå, Sweden. anne.lindberg@algmed.se.
authors.forename: Anne
authors.initials: A
authors.lastname: Lindberg
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, HUS Medical Imaging Centre, Helsinki University Central Hospital, Helsinki, Finland. anssi.sovijarvi@hus.fi.
authors.forename: Anssi
authors.initials: A
authors.lastname: Sovijärvi
authors.affiliation: Division of Physiology, the National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. kjell.larsson@ki.se.
authors.forename: Kjell
authors.initials: K
authors.lastname: Larsson
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine, the OLIN unit, Umeå university, Umeå, Sweden. bo.lundback@gu.se.|Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden. bo.lundback@gu.se.
authors.forename: Bo
authors.initials: B
authors.lastname: Lundbäck
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine, the OLIN unit, Umeå university, Umeå, Sweden. eva.ronmark@nll.se.|OLIN-Studierna, Robertsviksgatan 9, 97189, Lulea, Sweden. eva.ronmark@nll.se.
authors.forename: Eva
authors.initials: E
authors.lastname: Rönmark
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013147:Spirometry; D013548:Sweden; D014797:Vital Capacity / Q000502:physiology*; D055815:Young Adult