1. Department of Diabetology and Metabolism, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
2. Department of Internal Medicine, Yoyogi Hospital, Tokyo, Japan.
3. Department of Internal Medicine, Saitama-ken Saiseikai Kurihashi Hospital, Saitama, Japan.
4. Department of Internal Medicine, Josai Hospital, Tokyo, Japan.
5. Department of Medicine, Tokyo Women's Medical University Medical Center East, Tokyo, Japan.