1. Department of Health Sciences, Carleton University, Ottawa, Ontario, Canada
2. Institut Armand-Frappier, Institut national de la recherche scientifique (IAF-INRS), Laval, Quebec, Canada
3. Cancer Care Ontario, Toronto, Ontario, Canada
4. Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
5. Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA