1. Department of Epidemiology, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina, USA
2. Department of Pediatrics, Division of General and Community Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
3. Department of Environmental Health, Division of Epidemiology and Biostatistics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
4. Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
5. Child and Family Research Institute, BC Children’s Hospital and the Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada