1. Department of Epidemiology and Statistics, College of Public Health, Zhengzhou University, 100 Science Avenue, Zhengzhou 450001, Henan, China
2. Henan Key Laboratory of Tumor Epidemiology, Zhengzhou University, 40 Daxue Road, Zhengzhou 450052, China
3. Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital, Zhengzhou University, Zhengzhou 450052, Henan, China
4. Department of Teaching and Research, Henan Tumor Hospital, No. 127, Dongming Road, Zhengzhou 450003, Henan, China