1 1.Occupational Respiratory Epidemiology, School of Population Health, University of Western Australia, Perth, Australia; susan.peters@uwa.edu.au.
2 1.Occupational Respiratory Epidemiology, School of Population Health, University of Western Australia, Perth, Australia; 2.Respiratory and Sleep Medicine, Fiona Stanley Hospital, Perth, Australia;
3 3.School of Public Health, Curtin University, Perth, Australia;
4 1.Occupational Respiratory Epidemiology, School of Population Health, University of Western Australia, Perth, Australia; 4.Telethon Kids Institute, University of Western Australia, Perth, Australia;
5 1.Occupational Respiratory Epidemiology, School of Population Health, University of Western Australia, Perth, Australia; 3.School of Public Health, Curtin University, Perth, Australia;
6 1.Occupational Respiratory Epidemiology, School of Population Health, University of Western Australia, Perth, Australia;
7 5.Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia;
8 1.Occupational Respiratory Epidemiology, School of Population Health, University of Western Australia, Perth, Australia; 6.Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Perth, Australia.