1. Department of Environmental Health, Harvard University, Boston, Massachusetts, USA
2. Department of Epidemiology, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina, USA
3. National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
4. Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
5. Department of Pediatrics, University of Washington/Seattle Children’s Hospital, Seattle, Washington, USA
6. Department of Pediatrics, Division of General and Community Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
7. Simon Fraser University, Vancouver, British Columbia, Canada