[1] Chongqing Med Univ, Childrens Hosp, Dept Clin Epidemiol & Biostat,Chongqing Key Lab P, Natl Clin Res Ctr Child Hlth & Disorders,Minist E, Chongqing, Peoples R China
[2] Shandong Univ, Cheeloo Coll Med, Sch Publ Hlth, Dept Epidemiol, Jinan, Shandong, Peoples R China
[3] Jinan Univ, Sch Med, Dept Publ Hlth & Prevent Med, Guangzhou, Guangdong, Peoples R China