1. Division of Endocrinology, Diabetes and Metabolism, Hematology, Rheumatology (Second Department of Internal Medicine), Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
2. Department of Diabetes, Endocrinology and Metabolism, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
3. Department of Cardiology, Nakagami Hospital, Okinawa 904-2195, Japan
4. Department of Ophthalmology, Tomishiro Central Hospital, Okinawa 901-0243, Japan
5. Department of Diabetes and Life-style related Disease Center, Tomishiro Central Hospital, Okinawa 901-0243, Japan
6. Department of Ophthalmology, Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan