1. Department of Medicine, Division of Diabetes, Metabolism and Endocrinology Chiba University Hospital Chiba Japan
2. Department of Endocrinology, Hematology and Gerontology Chiba University Graduate School of Medicine Chiba Japan
3. Center for Preventive Medical Sciences Chiba University Chiba Japan
4. Department of Medicine, Division of Diabetes, Endocrinology and Metabolism Kimitsu Chuo Hospital Chiba Japan