1 Center for Clinical Epidemiology and Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China.
2 Department of Obstetrics, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, Gansu 730050, China.
3 Department of Cardiology, The First People's Hospital of Jiayuguan, Jiayuguan, Gansu 735100, China.
4 Respiratory Division of Zhongshan Hospital, Fudan University, Shanghai Respiratory Research Institute, Shanghai 200032, China.
5 Department of Anesthesiology, Central South University Xiangya Hospital 410000 Changsha, China.
6 Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, China.
7 Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing 100093, China.