1. Faculty of Medicine, Collegium Medicum, Cardinal Stefan Wyszynski University, 01-938 Warsaw, Poland
2. School of Public Health, Centre of Postgraduate Medical Education, 01-826 Warsaw, Poland
3. Department of Social Medicine and Public Health, Medical University of Warsaw, 02-007 Warsaw, Poland
4. Institute of Rural Health in Lublin, 20-090 Lublin, Poland