1. Economics Department, Brigham Young University, Provo, Utah, USA
2. Population Studies Division, Health Canada, Ottawa, Ontario, Canada
3. McLaughlin Center for Population Health Risk Assessment, University of Ottawa, Ottawa, Ontario, Canada
4. Health Effects Institute, Boston, Massachusetts, USA
5. Division of Environmental Health Science, School of Public Health, University of California, Berkeley, California, USA
6. Epidemiology Research Program, American Cancer Society, Atlanta, Georgia, USA