1. Department of Gastroenterology and Internal Medicine, Medical University of Białystok, Białystok, Poland
2. Department of Pediatrics, Gastroenterology, Hepatology, Nutrition and Allergology with the Pulmonology Subdivision, Medical University of Białystok, Białystok, Poland
3. Department of Hygiene, Epidemiology and Ergonomics, Medical University of Białystok, Białystok, Poland
4. Department of Public Health, Medical University of Białystok, Białystok, Poland