1. Department of Gynaecology and Obstetrics, Affiliated Xuancheng Hospital of Wannan Medical College, Xuancheng, Anhui Province, China
2. Department of General Medicine, Affiliated Xuancheng Hospital of Wannan Medical College, Xuancheng, Anhui Province, China
3. Department of Epidemiology and Statistics, School of Public Health, Medical College, Zhejiang University, Zhejiang, China
4. Department of General Medicine, Affiliated Anqing First People’s Hospital of Anhui Medical University, Hefei, China