1. PhD Candidate in Epidemiology; Student Research Committee, Faculty of Public Health Branch , Iran University of Medical Sciences ; Tehran ; Iran
2. Department of Biostatistics and Epidemiology, School of Health , Isfahan University of Medical Sciences , Isfahan , Iran .
3. Psychosomatic Research Center , Isfahan University of Medical Sciences , Isfahan , Iran
4. Department of Medicine , University of Alberta , Edmonton , Alberta , Canada .
5. Torbat Heydariyeh University of Medical Sciences , Torbat Heydariyeh , Iran .
6. Department of Internal Medicine, School of Medicine and Integrative Functional Gastrointestinal Disorders Research Center , Isfahan University of Medical Sciences , Isfahan , Iran .