1. Department of Health Behavior Gillings School of Global Public Health, University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
2. Carolina Population Center, University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
3. Department of Nutrition Gillings School of Global Public Health, University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
4. Department of Pediatrics Stanford University School of Medicine Palo Alto California USA
5. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill Chapel Hill North Carolina USA