[1] Med Univ Plovdiv, Dept Gen & Clin Pathol, Plovdiv 4000, Bulgaria
[2] Sofia Univ St Kliment Ohridski, Fac Biol, Dept Genet, Sofia 1164, Bulgaria
[3] Univ Hosp Lozenetz, Dept Gastroenterol, Sofia 1407, Bulgaria
[4] Med Univ Plovdiv, Dept Thoraco Abdominal Surg, Plovdiv 6000, Bulgaria
[5] Univ Clin Digest Surg, Med Fac, Skopje 1000, North Macedonia
[6] Heart & Brain Hosp, Dept Gastroenterol, Burgas 1000, Burgas, Bulgaria
[7] Med Univ, Naval Hosp Varna, Mil Med Acad, Med Fac,Clin Internal Dis, Varna 9000, Bulgaria
[8] Mil Med Acad, Naval Hosp Varna, Clin Internal Dis, Varna 9010, Bulgaria
[9] Univ Hosp Alexandrovska, Clin Endocrinol, Sofia 1431, Bulgaria
[10] Med Univ Sofia, Dept Internal Dis, Sofia 1431, Bulgaria
[11] UMHAT Sv Georgi, Clin Endocrinol & Metab Disorders, Plovdiv 4000, Bulgaria
[12] Univ Hosp Lozenetz, Dept Anesthesiol & Intens Care, Sofia 1407, Bulgaria
[13] Sofia Univ St Kliment Ohridski, Med Fac, Sofia 1407, Bulgaria
[14] Univ Hosp NI Pirogov, Dept Pediat, Sofia 1606, Bulgaria
[15] Fac Publ Hlth Prof Tsekomir Vodenicharov, Dept Healthcare, Sofia 1527, Bulgaria
[16] New Bulgarian Univ, Dept Informat, Sofia 1618, Bulgaria
[17] Sofia Univ St Kliment Ohridski, Med Fac, Sofia 1407, Bulgaria
[18] Med Univ Plovdiv, Dept Gen & Clin Pathol, Bul Vasil Aprilov 15A, Plovdiv 4000, Bulgaria