1. School of Public HealthGuangdong Medical UniversityDongguanGuangdong Province 523808P.R. China
2. Department of ChemotherapyThe People's Hospital of GaoZhouGaoZhouGuangdong Province 523808P.R. China
3. Department of Gastrointestinal surgeryShandong Provincial Hospital Affiliated to Shandong UniversityJinan 250021Shandong ProvinceP.R. China
4. Research Institute of the Aged Care IndustryGuangdong Medical UniversityGuangdongGuangdong Province 523808P.R. China