[1] Cent South Univ, Affiliated Childrens Hosp, Hunan Childrens Hosp, Pediat Res Inst Hunan Prov,Xiangya Sch Med, Changsha 410007, Peoples R China
[2] Zhengzhou Univ, Coll Publ Hlth, Dept Epidemiol & Biostat, Zhengzhou 450000, Henan, Peoples R China
[3] Cent South Univ, Affiliated Childrens Hosp, Hunan Childrens Hosp, Dept Neonatol,Xiangya Sch Med, Changsha 410007, Peoples R China
[4] Cent South Univ, Univ South China, Affiliated Childrens Hosp, Hunan Childrens Hosp,Xiangya Sch Med,Hunan Prov Ke, Changsha, Peoples R China