1. Family Planning and Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
2. Faculty of Medicine and Biomedical Sciences, The University of Yaoundé I, P.O. Box 3011, Messa, Yaoundé, Cameroon
3. School of Nursing, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
4. Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
5. Department of Trauma Surgery, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
6. Department of Orthopaedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
7. Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China