1. Department of Epidemiology, College of Preventive Medicine, Third Military Medical University, Chongqing, China
2. Department of Environmental Health, School of Public Health, Fudan University, Shanghai, China
3. Information Department Medical Record Room, Second Affiliated Hospital, Fourth Military Medical University, Xi’an, China
4. School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania, USA
5. School of Public Health, Fourth Military Medical University, Xi’an, China