1. Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada;
2. Department of Community Health and Epidemiology, Dalhousie University, Halifax, Nova Scotia, Canada;
3. Pulmonary, Critical Care, Allergy, and Sleep Medicine, University of California San Francisco, San Francisco, California;
4. Department of Respiratory and Sleep Medicine, Austin Hospital, Heidelberg, Germany;
5. Lung Function & Sleep, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom;
6. Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico;
7. Pulmonary Function Laboratory, Elliot Health System, Manchester, New Hampshire;
8. Pulmonary Disease and Critical Care Medicine, University of Vermont College of Medicine, Burlington, Vermont;
9. University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam;
10. Department of Paediatrics and Child Health, Faculty of Health Sciences, School of Clinical Medicine, University of Kwazulu-Natal, Durban, South Africa;
11. Division of Pulmonary and Critical Care, Johns Hopkins School of Medicine, Baltimore, Maryland; and
12. Pulmonary Function Unit, Isala Hospital, Zwolle, the Netherlands