1. Department of Internal Medicine, Endocrine Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
2. The Graduated School Yonsei University, Seoul, Korea.
3. Department of Internal Medicine, Kwandong University College of Medicine, Incheon, Korea.
4. Department of General Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.