Affiliation: | 1. Department of Pediatric Endoscopy and Gastrointestinal Function Testing, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Bydgoszcz, Poland;2. Anna Szaflarska‐Pop?awska, Department of Pediatric Endoscopy and Gastrointestinal Function Testing, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland.;3. Department of Pediatrics, Gastroenterology, Cardiology, Neurology, Endocrynology and Diabetology, Dr W?adys?aw, Biegański Regional Specialist Hospital in Grudzi?dz, Grudziadz, Poland |