1. Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Division of Respiratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Centre for Clinical Epidemiology and Evaluation,
Vancouver Coastal Health Research Institute, Vancouver
2. Centre for Health Evaluation and Outcome Sciences, St Paul's Hospital, Vancouver, Collaboration for Outcomes Research and Evaluation, University of British Columbia, Vancouver
3. Division of Respiratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Centre for Clinical Epidemiology and Evaluation, Vancouver Coastal Health Research Institute, Vancouver, Institute for Heart and Lung Health,
University of British Columbia, Vancouver, British Columbia
4. Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Respiratory Epidemiology and Clinical Research Unit, McGill University Health Centre, Montreal
5. Department of Family Medicine, McGill University, Montreal, Quebec, Canada
6. Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec