1. Department of Epidemiology and Public Health, Faculty of Medicine, University of Ostrava, Ostrava, Czech Republic
2. Department of Nursing and Midwifery, Faculty of Medicine, University of Ostrava, Ostrava, Czech Republic
3. Department of Surgery, University Hospital Ostrava and Faculty of Medicine University of Ostrava, Ostrava, Czech Republic
4. Institute of Hygiene, Faculty of Medicine, Comenius University in Bratislava, Slovak Republic