1 Division of Pulmonary Medicine, Department of Pediatrics, UPMC Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pa.
2 Behavioral Sciences Research Institute, University of Puerto Rico, San Juan, Puerto Rico.
3 Division of Pulmonary Medicine, Department of Pediatrics, UPMC Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pa. Electronic address: juan.celedon@chp.edu.