TY - JOUR T1 - Evaluation of the Global Lung Function Initiative reference equations in Belgian adults JF - ERJ Open Research JO - erjor DO - 10.1183/23120541.00671-2021 VL - 8 IS - 2 SP - 00671-2021 AU - Kevin De Soomer AU - Evelyn Pauwels AU - Hilde Vaerenberg AU - Eric Derom AU - Lidia Casas AU - Johan Verbraecken AU - Thérèse Lapperre AU - Ellie Oostveen Y1 - 2022/04/01 UR - http://openres.ersjournals.com/content/8/2/00671-2021.abstract N2 - Background Over the past decade, the Global Lung Function Initiative (GLI) Network has published all-age reference equations on spirometry, diffusing capacity of the lung for carbon monoxide (DLCO) and lung volumes.Methods We evaluated the appropriateness of these equations in an adult Caucasian population. Retrospective lung function data on subjects who performed tests prior to a diagnostic sleep investigation were analysed. From the medical records, lung healthy, lifetime nonsmoking, nonobese subjects were selected, resulting in a population of 1311 subjects (68% male; age range 18–88 years).Results Multiple linear regression analysis revealed that lung function z-scores did not differ between subjects with and without sleep apnoea but did depend on height and age. The average forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) z-score was 0 but exhibited an inverse association with height in both sexes (p<0.01). Values of FEV1 and FVC in both sexes were larger than predicted (mean±sd z-score +0.30±0.96 or 104±13% pred; p<0.01). Overall, static lung volumes and DLCO were adequately predicted. However, DLCO z-scores were inversely associated with height in males and age in females (p<0.01). For all lung function indices, the observed scatter was reduced compared with the prediction. Therefore, for all indices <5% of the data were below the GLI-proposed lower limit of normal (LLN) threshold.Conclusion GLI reference equations provide an adequate fit in Belgian adults. However, the GLI-proposed LLN is too low for our Antwerp population, resulting in underdiagnosis of disease. Furthermore, airway obstruction and diffusion disorders might be misclassified due to height and age associations.Overall, GLI reference equations for lung function appropriately describe the data in Belgian adults. However, airway obstruction and diffusion disorders might be misdiagnosed at age and height extremes, and the GLI LLN was too low in this population. https://bit.ly/3jdauLE ER -