1. Shunde Hospital of Southern Medical University, Foshan, Guangdong 528308, P.R. China
2. The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 570100, P.R. China
3. Department of Endocrinology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510000, P.R. China
4. Shenzhen Nan Shan Hospital, Shenzhen, Guangdong 518052, P.R. China