1. Injury Prevention Research Center, University of North Carolina at Chapel Hill, USA
2. Pacific Institute for Research and Evaluation, Chapel Hill, North Carolina, USA
3. Department of Emergency Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
4. Department of Epidemiology, Gillings School of Global Public Health, USA
5. Division of General Pediatrics & Adolescent Medicine, Department of Pediatrics, School of Medicine, USA
6. Division of General Medicine & Clinical Epidemiology, Department of Medicine, School of Medicine, USA
7. Cecil G Sheps Center for Health Services Research, University of North Carolina at Chapel Hill, Chapel Hill, USA
8. North Carolina Division of Public Health, Chronic Disease and Injury Section, Raleigh, USA
9. Department of Health Policy and Management, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA