1. Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea.
2. Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon, Korea.
3. National Health Insurance Corporation Ilsan Hostpital, Goyang, Korea.
4. Department of Internal Medicine, Hallym University Medical College, Chuncheon, Korea.
5. Department of Pediatrics, The Catholic University of Korea, Seoul, Korea.