1 Tianjin Centers for Disease Control and Prevention, Tianjin 300011, China; Department of Occupational and Environmental Health, School of Public Health, Peking University Health Science Center.
2 Department of Occupational and Environmental Health, School of Public Health, Peking University Health Science Center.
3 Department of Occupational and Environmental Health, School of Public Health, Peking University Health Science Center. Email: xcpan@bjmu.edu.cn.