1. Evidence Based Social Science Research Center, School of Public Health, Lanzhou University, Lanzhou, China.
2. Key Laboratory of Evidence Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, China.
3. Department of Epidemiology and Health Statistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.
4. The Zhongshan Affiliated Hospital, Fudan University, Shanghai, China.
5. The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
6. Institute for Evidence Based Rehabilitation Medicine of Gansu Province, Lanzhou, China.
7. Evidence Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.