1. Department of Epidemiology, Boston University School of Public Health, Boston University, Boston, Massachusetts
2. Department of Global Health, Boston University School of Public Health, Boston University, Boston, Massachusetts
3. Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
4. Department of Pediatrics, McGill University, Montreal, Quebec, Canada
5. Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada
6. Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts-Amherst, Amherst, Massachusetts