1. Division of Maternal and Child Nursing, School of Nursing, Peking University Health Science Centre, No 38 Xueyuan Road, Haidian District, Beijing 100191, China
2. Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, No 10 Xi Tou Tiao, Fengtai District, Beijing 100069, China
3. Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, No 10 Xi Tou Tiao, Fengtai District, Beijing 100069, China
4. Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, No 167 North Lishi Road, Xicheng District, Beijing 100037, China