1. Department of Epidemiology, Cardiovascular Disease Prevention and Health Promotion, National Institute of Cardiology , Warsaw , Poland
2. Department of Demography , University of Łódź , Łódź , Poland
3. Mossakowski Medical Research Centre, Polish Academy of Sciences , Warsaw , Poland
4. National Centre for Sports Medicine , Warsaw , Poland
5. MD student at the Medical University of Warsaw – English Division
6. Department of Preventive and Social Medicine , Medical University of Łódź , Łódź , Poland