1. ICF International, Reston, Virginia, USA.
2. Center for Child Health, Behavior, and Development, Seattle Children's Research Institute, Seattle, Washington, USA.
3. Harborview Medical Center, University of Washington School of Medicine, Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, USA.
4. College of Health and Human Services, School of Exercise and Nutritional Sciences, San Diego State University, San Diego, California, USA.
5. Harborview Injury Prevention and Research Center, Department of Pediatrics, Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, USA.
6. Psychiatry and Behavioral Sciences, University of Washington, Seattle Children's Hospital, Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, USA.
7. Department of Pediatrics, Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, USA.