Abstract
Background: In 2012 the Global Lung Function Initiative (GLI) published international reference values for the age range 3 to 95 years. We aimed to study the validity of GLI equations in Norwegians, and to compare them with currently used national (Gulsvik, Langhammer) and international (ECSC, Zapletal) equations in Norway.
Methods: Spirometry data were included from random samples in three general population based studies; the Tromsø 6 Study, the Hordaland County Cohort Study, and the Nord-Trøndelag Health Study. Spirometry was performed at least once by 14,625 adults aged 20-90 years and 15,458 persons aged 12-19 years. The reference sample included never-smoking persons without self-reported respiratory symptoms or disease. The percent predicted values and z-scores for each subject were calculated by use of the GLI software and equations already in use in Norway, and the goodness of fit evaluated.
Results: In total 1508 female and 1106 male adults and 4729 female and 4946 male adolescents met the inclusion criteria. The GLI-2012 prediction equation fitted the Norwegian data quite well. Average (SD) Z-scores (observed minus predicted /standard deviation) were 0.04 (1.03), 0.06 (1.04) and -0.06 (0.88) for FEV1, FVC and FEV1/FVC in men, respectively, and -0.01 (1.01), 0.11 (0.98) and -0.28 (0.79) in women, respectively. Hence the agreement between spirometric indices in a Norwegian population and predicted values by GLI-2012 was good; the ECSC and Zapletal's prediction equations significantly underestimated FEV1 and FVC among adults and adolescents.
Conclusions: The GLI-2012 reference values seem to fit Norwegian spirometry data quite well but may somewhat underestimate the prevalence of a low FVC in adults.
- Copyright ©ERS 2015