1. Departments of Pediatrics and
2. Center for Child Health, Behavior and Development, Seattle Children’s Research Institute, Seattle, Washington;
3. Epidemiology, and
4. Harborview Injury Prevention and Research Center, University of Washington, Seattle, Washington;
5. Department of Epidemiology, Program for Injury Prevention Education and Research, Colorado School of Public Health at the University of Colorado Anschutz, Aurora, Colorado; and
6. Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado