1. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Cancer Epidemiology, Peking University Cancer Hospital, Beijing, China
2. Linqu County People’s Hospital, Linqu County People’s Hospital, Linqu, China
3. Department of Disease Control, Department of Disease Control, Linqu County Public Health Bureau, Linqu 262600, China, Linqu, China
4. Department of Disease Control,, Linqu County Public Health Bureau, Linqu, China
5. Department of Epidemiology, Institute for Gastric Cancer Prevention, Linqu, China