Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 44 4 2015 04 15 583 5 Jun Tu Chengdu Municipal Center for Disease Control and Prevention, Chengdu, Sichuan, China. Ke-Jian Liu Dept. of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China. Long-Ju Ran Chengdu Municipal Center for Disease Control and Prevention, Chengdu, Sichuan, China. Xing-Ping Pan Chengdu Municipal Center for Disease Control and Prevention, Chengdu, Sichuan, China. 2015 10 14 No Abstract https://ijph.tums.ac.ir/index.php/ijph/article/view/3577 https://ijph.tums.ac.ir/index.php/ijph/article/download/3577/3252