1. Department of Endocrinology; Tengzhou Central People's Hospital; Shandong China
2. Zaozhuang Science and Technology College; Shandong China
3. Department of Medicine; Maternal and Child Care Service Centre of Tengzhou City; Shandong China
4. Division of Endocrinology and Diabetology; Department of Internal Medicine II; University Hospital of Freiburg; Freiburg Germany