1. Evidence‐Based Medicine Center School of Basic Medical Sciences Lanzhou University Lanzhou PR China
2. Key Laboratory of Evidence Based Medicine and Knowledge Translation of Gansu Province Lanzhou PR China
3. Chinese GRADE Centre Lanzhou University Lanzhou PR China
4. Taiyuan Central Hospital Taiyuan PR China
5. Department of Epidemiology and Health Statistics West China School of Public Health and West China Fourth Hospital Sichuan University Chengdu PR China
6. Gansu Provincial Maternity and Child Care Hospital Lanzhou PR China