1. Behbahan Faculty of Medical Sciences, Behbahan, Iran
2. Shiraz HIV/AIDS Research Center, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran
3. Colorectal Research Center, Faghihi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
4. Department of Epidemiology, Faculty of Public Health, Shiraz University of Medical Sciences, Shiraz, Iran