[1] Sungkyunkwan Univ, Sch Med, Kangbuk Samsung Hosp, Div Endocrinol & Metab,Dept Internal Med, Seoul 110746, South Korea
[2] Hallym Univ, Coll Med, Dept Internal Med, Pyungchon, South Korea
[3] Catholic Univ Korea, Coll Med, Dept Internal Med, Seoul, South Korea