1. Diabetes Therapeutics and Research Center, Institute of Advanced Medical Sciences, Tokushima University, Tokushima 770-8503, Japan
2. Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
3. Department of Preventive Medicine, Iizuka Hospital, Iizuka 820-8505, Japan
4. Muta Hospital, Fukuoka 814-0163, Japan