1. Department of Occupational and Environmental Health, School of Public Health, Guangxi Medical University, Nanning 530021, China
2. Department of Epidemiology and Health Statistics, School of Public Health, Guangxi Medical University, Nanning 530021, China
3. Global Health Research Center, Duke Kunshan University, Kunshan 215316, China
4. Boston University School of Medicine, Boston Medical Center, Boston, MA 02118, USA