1. Asthma Research Unit, Kingston Health Sciences Centre, Kingston, Ontario, Canada
2. Department of Medicine, Queen’s University, Kingston, Ontario, Canada
3. Department of Family Medicine, University of Calgary, Calgary, Alberta
4. Department of Public Health Sciences, Queen’s University, Kingston, Ontario, Canada
5. Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
6. Department of Medicine, Dalla Lana School of Public Health, University of Toronto
7. Respiratory Division, University Health Network, Toronto, Ontario, Canada