1. Dalla Lana School of Public Health, University of Toronto, Toronton, ON M5T 3M7, Canada
2. Center for Addictions and Mental Health, Toronto, ON M6J 1H4, Canada
3. Department of Otolaryngology—Head and Neck Surgery, Temerty Faculty of Medicine, Sunnybrook Hospital, Toronto, ON M4N 3M5, Canada
4. Ontario Tobacco Research Unit, Toronto, ON M5S 2S1, Canada