1. Preventative Gynecology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2. Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
3. Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
4. Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
5. School of Medicine, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran