Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York, United States.|Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, P.R. China.|Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, P.R. China.|State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, P.R. China.|Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, P.R. China.|Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York, United States.