[Hu, Fan; Li, Mei; Wang, Wei; Xu, Chongsi; Xiao, You] Hunan Univ Tradit Chinese Med, Affiliated Hosp 2, Dept Anorectal 5, Changsha, Peoples R China.
[He, Yuanyuan] Hunan Univ, Hunan Univ Chinese Med, Grad Sch, Changsha, Peoples R China.
[Wang, Zhenquan] Hunan Univ Tradit Chinese Med, Affiliated Hosp 2, Dept Anorectal 3, Changsha 410005, Peoples R China.
[Cao, Yi] Univ South China, Hengyang Med Sch, Sch Publ Hlth, Hunan Prov Key Lab Typ Environm Pollut & Hlth Haza, Hengyang, Peoples R China.