1 Department of Epidemiology, Biostatistics and Occupational Health, McGill University, and Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre.
2 Professor of Medicine, Department of Epidemiology, Biostatistics and Occupational Health, McGill University, and Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada. [email protected].