1. Department of Endocrinology, Metabolism and Nephrology, Kochi Medial School, Kochi University, Kochi 783-8505, Japan
2. Faculty of Health Science, Suzuka University of Medical Science, Mie 510-0293, Japan
3. Health Service Center, Kochi Medial School, Kochi University, Kochi 780-8520, Japan
4. Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA