1. School of Public Policy and Administration, Xi’an Jiaotong University, Xi’an 710049, China
2. School of Public Health, Health Science Center, Xi’an Jiaotong University, Xi’an 710061, China
3. Center of Health Information of Shaanxi Province, Xi’an 710003, China
4. The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061, China