1. Department of Diabetes, Endocrinology and Hematology, Dokkyo Medical University Saitama Medical Center, Saitama 343-8555, Japan
2. Department of Diabetes Mellitus, Saitama Cooperative Hospital, Saitama 333-0831, Japan
3. Collaborative Research Center, Dokkyo Medical University Saitama Medical Center, Saitama 343-8555, Japan