1 Department of Child, Adolescent Health and Maternal Care, School of Public Health, Capital Medical University, China.
2 Department of Vascular Surgery, Beijing Luhe Hospital, Capital Medical University, China. Electronic address: xwhvs@163.com.
3 Department of Child, Adolescent Health and Maternal Care, School of Public Health, Capital Medical University, China; UNESCO Chair on Global Health and Education, Peking University, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, China. Electronic address: huyifei@yahoo.com.