1. Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec H3A 1A2, Canada;,
2. Institute for Health and Social Policy, McGill University, Montreal, Quebec H3A 1A2, Canada
3. Department of Public Health, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
4. Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, California 94720, USA;
5. Biomedical Ethics Unit, McGill University, Montreal, Quebec H3A 1X1, Canada