[1
]
Department of Pediatrics, Uniformed Services University of Health Sciences, Bethesda,
MD.
[2
]
Department of Pediatrics, Emory University School of Medicine and Children's Healthcare
of Atlanta, Atlanta, GA.
[3
]
Duke Clinical Research Institute, Duke University Medical Center, Durham, NC. Electronic
address: brian.smith@duke.edu.
[4
]
Department of Pediatrics, Womack Army Medical Center, Fort Bragg, NC.
[5
]
Department of Biostatistics, University of North Carolina School of Public Health,
Chapel Hill, NC.
[6
]
Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill,
NC.