1. Department of Epidemiology and Health Statistics, School of Public Health, Fujian Medical University, Fujian, China
2. Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fujian, China
3. Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital of Fujian Medical University, Fujian, China
4. Nagasaki Prefectural Institute of Environmental Research and Public Health, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
5. Department of Public Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan