1. Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA;
2. Department of Speech-Language Pathology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA;
3. Biostatistics Analysis Center, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA;
4. Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
5. Division of Pediatric Allergy and Immunology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.