[1] Univ Athens, Sch Med, Alexandra Hosp, Dept Clin Therapeut, Athens 11521, Greece
[2] Univ Athens, Sch Med, Hippocrateio Hosp, Propaedeut Surg Dept 1, Athens 11521, Greece
[3] Univ Athens, Sch Med, Dept Hyg Epidemiol & Med Stat, Athens 11521, Greece