title: Spirometric reference equations for Swedish adults.
abstract: New spirometric reference equations for Swedish adults are required. Three different older sets of reference equations clinically used in Sweden have various drawbacks and the recently published 'The Global Lung Function 2012 (GLI) equations' have been shown not to be adequate for Swedish normal, healthy non-smokers. We have recently concluded that a piecewise linear model presented by Lubinski and Gólczewski accurately describes the distribution of spirometric variables in a large Swedish random population sample. This piecewise linear model also offers the important advantage of implementing easily physiologically interpretable coefficients. The present study aimed at presenting piecewise linear reference equations for Swedish adults based on a random population sample of 6685 individuals aged 25-75 years. Predicted normal values by the piecewise linear reference equations and lower limit normal (LLN) were compared with the three reference equations frequently used clinically in Sweden and the GLI equations. We found predicted normal values according to the present piecewise linear reference equations close to 100% predicted normal as expected, whereas the other equations either overestimated or underestimated normal subjects. Concerning LLN, the present equations, i.e. 1·645 × RSD, showed the least deviation from the expected 5% and, e.g., the GLI equations systematically identified too few subjects below LLN. We conclude that the present piecewise linear reference equations, based on a relatively large general population sample, ought to be considered for clinical use in Sweden. Application of 1·645 × RSD below predicted value gave an acceptably accurate LLN.
authors: Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.|Occupational and Environmental Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors: Jonas
authors: J
authors: Brisman
authors: Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.|Occupational and Environmental Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors: Jeong-Lim
authors: JL
authors: Kim
authors: Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.|Occupational and Environmental Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors: Anna-Carin
authors: AC
authors: Olin
authors: Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.|Occupational and Environmental Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors: Kjell
authors: K
authors: Torén
authors: Occupational and Environmental Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Respiratory Medicine and Allergology, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors: Björn
authors: B
authors: Bake
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume; D064368:Healthy Volunteers; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D012016:Reference Values; D013147:Spirometry / Q000592:standards*; D013548:Sweden; D014797:Vital Capacity
keywords: adults; general population sample; lower limit normal; lung function; normal values; prediction