1. Department of Urology, Veterans Health Service Medical Center, Seoul, Korea.
2. Seonyudo Public Health Subcenter, Gunsan, Korea.
3. Department of Urology, Eulji General Hospital, Eulji University School of Medicine, Seoul, Korea.
4. Department of Urology, Seoul National University Bundang Hospital, Seongnam, Korea.
5. Department of Family Medicine, Veterans Health Service Medical Center, Seoul, Korea.