1. Department of Internal Medicine and Gastroenterology, Polish Red Cross Memorial Municipal Hospital, 79 Henryk Sienkiewicz Street, 15-003 Bialystok, Poland
2. Department of Medical Biology, Medical University of Bialystok, 2C Adam Mickiewicz Street, 15-222 Bialystok, Poland
3. Department of Hygiene, Epidemiology and Metabolic Disorders, Medical University of Bialystok, 2C Adam Mickiewicz Street, 15-222 Bialystok, Poland