1. Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
2. Division of Diabetes and Metabolism, Institute for Adult Diseases, Asahi Life Foundation, 2-2-6, Bakuro-cho, Chuo-ku, Tokyo 103-0002, Japan
3. Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake-cho, Miyazaki, Miyazaki 889-1692, Japan
4. Division of Diabetes and Metabolic Diseases, Nihon University School of Medicine, 30-1, Oyaguchi Kami-cho, Itabashi-ku, Tokyo 173-8610, Japan
5. Department of Medical Science, Graduate School of Medicine, University of Hiroshima, 1-2-3 Kasumi, Minami-ku, Hiroshima, Hiroshima 734-8551, Japan
6. Department of Diabetes and Metabolic Diseases, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan