Gastroenterology and Liver Diseases Research Center,Research Institute for Gastroenterology and Liver Diseases,Shahid Beheshti University of Medical Sciences;
Department of Biostatistics,Shahid Beheshti University of Medical Sciences;
Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center,Research Institute for Gastroenterology and Liver Diseases,Shahid Beheshti University of Medical Sciences;
Department of Biostatistics,University of Social Welfare and Rehabilitation Sciences;