1 Division of Adolescent and Young Adult Medicine, University of Pittsburgh School of Medicine, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15213, USA. Electronic address: elizabeth.miller@chp.edu.
2 School of Nursing, George Mason University, Fairfax, VA, USA.
3 UC San Diego School of Medicine, San Diego, CA, USA; Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA.
4 Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
5 Johns Hopkins School of Nursing, Baltimore, MD, USA.