1 Centre for Clinical Epidemiology, Lady Davis Institute - Jewish General Hospital, Montreal, QC, Canada; Departments of Epidemiology and Biostatistics, and Medicine, McGill University, Montreal, QC, Canada. Electronic address: samy.suissa@mcgill.ca.
2 Centre for Clinical Epidemiology, Lady Davis Institute - Jewish General Hospital, Montreal, QC, Canada; Departments of Epidemiology and Biostatistics, and Medicine, McGill University, Montreal, QC, Canada.