Department of Endocrinology and Diabetes, Saitama Medical University Hospital, Saitama 350-0495, Japan. Caress Sapporo Hokko Memorial Clinic, Hokkaido 065-0027, Japan. Department of Endocrinology, Tenri Hospital, Nara 632-8552, Japan. Department of Endocrinology and Diabetes, Japanese Red Cross Ogawa Hospital, Saitama 355-0397, Japan. Department of Medicine, Division of Endocrinology and Metabolism, Jichi Medical University Saitama Medical Center, Saitama 330-8503, Japan. Department of Medicine II, Kansai Medical University, Osaka 573-1191, Japan. Department of Endocrinology, Metabolism and Hypertension Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan. Division of Diabetes and Endocrinology, Japanese Red Cross Omori Hospital, Tokyo 143-8527, Japan. Department of General Internal Medicine, Saitama Medical University Hospital, Saitama 350-0495, Japan. Department of Diabetes, Metabolism and Endocrinology, Ichikawa Hospital, International University of Health and Welfare, Chiba 272-0827, Japan.