1. Colorectal Research Center, Department of epidemiology, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
2. Department of Anesthesia, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
3. Department of Epidemiology, School of Health, Shiraz University of Medical Sciences, Shiraz Fars, Iran
4. Department of Biostatistic, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
5. Department of Physiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran