1. Department of Internal Medicine, Clinic of Endocrinology, University Hospital “Alexandrovska” Medical University, Georgi Sofiyski 1 Str., 1431 Sofia, Bulgaria
2. Department of Epidemiology and Hygiene, Medical University of Sofia, 1431 Sofia, Bulgaria
3. Department of Diagnostic Imaging, Medical University, 1431 Sofia, Bulgaria
4. Clinic of Cardiology, SHATC “Medica Cor” EAD, 7000 Rousse, Bulgaria
5. Medical Faculty, Sofia University St. Kliment Ohridski, 1407 Sofia, Bulgaria