1. Department of Epidemiology, School of Public Health, China Medical University, Shenyang, China
2. Liaoning Provincial Department of Education, Key Laboratory of Cancer Etiology and Prevention, China Medical University, Liaoning, China
3. Department of Epidemiology, School of Public Health, Shenyang Medical College, Shenyang, China
4. Department of Radiotherapy, The Fourth Affiliated Hospital of China Medical University, Shenyang, China