[1] University of Belgrade,Clinic for Obstetrics and Gynecology, Clinical Center of Serbia, Faculty of Medicine
[2] University of Belgrade,Institute of Medical Statistics and Informatics, Faculty of Medicine
[3] University of Belgrade,Dietetic Unit, Institute of Hygiene and Medical Ecology, Faculty of Medicine
[4] University of Belgrade,Clinic for ENT/MFH, Clinical Center of Serbia, Faculty of Medicine
[5] University of Belgrade,Institute of Epidemiology, Faculty of Medicine