1. Department of Dermatology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
2. Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
3. Department of Biostatistics, The Catholic University of Korea, Seoul, Korea.
4. Department of Statistics and Actuarial Science, Soongsil University, Seoul, Korea.