1. Department of Endocrinology and Metabolism, Peking University People's Hospital, Peking University Diabetes Center. No. 11 , Beijing 100044 , China
2. Department of Endocrinology, Beijing Airport Hospital. No. 49 , Beijing 101318 , China
3. Department of Endocrinology, Capital Medical University Beijing Tiantan Hospital. No. 119 , Beijing 100050 , China
4. Department of Endocrinology, Beijing Pinggu Hospital. No. 59 , Beijing 101200 , China