[1] Shahid Beheshti Univ Med Sci, Gastroenterol & Liver Dis Res Ctr, Res Inst Gastroenterol & Liver Dis, Tehran, Iran
[2] Shahid Beheshti Univ Med Sci, Res Inst Gastroenterol & Liver Dis, Foodborne & Waterborne Dis Res Ctr, Shahid Arabi Ave,Yemen St, Tehran, Iran
[3] Shahid Beheshti Univ Med Sci, Res Inst Gastroenterol & Liver Dis, Basic & Mol Epidemiol Gastrointestinal Disorders, Tehran, Iran
[4] Oita Univ, Dept Environm & Prevent Med, Fac Med, Oita, Japan