1. Department of Epidemiology and Biostatistics, School of Public Health, Anhui Hefei, China
2. School of Stomatology, Anhui Medical University, Anhui Hefei, China
3. Department of Human Resource, The Second Affiliated Hospital of Anhui Medical University, Anhui Hefei, China
4. Department of health inspection and quarantine, School of Public Health, Anhui Medical University, Anhui Hefei, China