1. Department of General Surgery, School of Medicine, Firoozabadi Hospital, Iran University of Medical Sciences
2. Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
3. York University, Toronto, Canada
4. Department of Public Health, College of Health and Human Services, California State University, Fresno, California, USA
5. School of Medicine, Mashad University of Medical Sciences, Mashad
6. Tabriz University of Medical Sciences, Tabriz, and
7. Department of Orthopedic Surgery, Urmia University of Medical Sciences, Urmia, Iran