1. Division of Diabetes and Endocrinology, Department of Internal Medicine, Jikei University Daisan Hospital, Tokyo, Japan.
2. Department of Internal Medicine, Shin-Yamanote Hospital, Higashi-murayama, Japan.
3. Cardiovascular Medical & Surgical Center, Shin-Yamanote Hospital, Higashi-murayama, Japan.
4. Division of Diabetes and Endocrinology, Department of Internal Medicine, Jikei University School of Medicine, Minato-ku, Japan.