1. Department of Pediatrics, Skaraborg Central Hospital, Skövde, Sweden
2. Occupational and Environmental Medicine, School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
3. Department of Respiratory and Sleep Medicine, Queensland Children’s Hospital, Brisbane, QLD, Australia
4. Children’s Health and Environment Program, Child Health Research Centre, University of Queensland, Brisbane, QLD, Australia
5. Airway Physiology and Imaging Group, Woolcock Medical Research Institute, Sydney, NSW, Australia