[1] Xi An Jiao Tong Univ, Affiliated Hosp 1, Dept Gastroenterol, Xian 710061, Peoples R China
[2] Clin Med Res Ctr Digest Dis Oncol Shaanxi Prov, Xian 710061, Peoples R China
[3] Thamar Univ, Fac Med, Dept Gastroenterol, Thamar, Yemen
[4] Hodeidah Univ, Fac Med Sci, Dept Med Labs, Hodeidah, Yemen
[5] Xi An Jiao Tong Univ, Hlth Sci Ctr, Sch Publ Hlth, Dept Epidemiol & Biostat, Xian, Shaanxi, Peoples R China
[6] Natl Inst Publ Hlth Res INRSP, Dept Epidemiol, Nouakchott BP 695, Nouakchott, Mauritania
[7] Ibb Univ, Fac Med, Dept Gen Surg, Ibb, Yemen
[8] Xi An Jiao Tong Univ, Hlth Sci Ctr, Dept Biochem & Mol Biol, Key Lab Environm & Genes Related Dis,Minist Educ, Xian, Peoples R China
[9] Thamar Univ, Fac Med, Dept Internal Med, Thamar, Yemen