1. Department of General Surgery, Suzhou Medical College of Soochow University, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, Jiangsu, China
2. Shandong Institute of Prevention and Control for Endemic Disease, Jinan, Shandong, China
3. Qingdao Municipal Center for Disease Control and Prevention, Qingdao Institute of Preventive Medicine, Qingdao, Shandong, China
4. Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, China