1. Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul National University Hospital , Seoul 03080 , Korea
2. Department of Surgery, Seoul National University Hospital , Seoul 03080 , Korea
3. Department of Surgery, Seoul National University Bundang Hospital , Seongnam 13620 , Korea
4. Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul National University Bundang Hospital , Seongnam 13620 , Korea
5. Medical Research Collaborating Center, Seoul National University Hospital , Seoul 03080 , Korea