1. Division of Endocrinology, Diabetes and Metabolism, Hematology, Rheumatology (Second Department of Internal Medicine), Graduate School of Medicine, University of the Ryukyus, Okinawa
2. Department of Bioresources Engineering, National Institute of Technology, Okinawa College, Okinawa
3. Department of Diabetes, Endocrinology and Metabolism, Fukushima Medical University, Fukushima, Japan