1. Department of Internal Medicine; College of Medicine; The Catholic University of Korea; Seoul Korea
2. Division of Endocrinology and Metabolism; Department of Internal Medicine; Seoul St. Mary's Hospital; Seoul Korea
3. Department of Medical Statistics; College of Medicine; The Catholic University of Korea; Seoul Korea
4. Division of Endocrinology and Metabolism; Department of Internal Medicine; Yeouido St. Mary's Hospital; Seoul Korea
5. Department of Epidemiology and Biostatistics; Arnold School of Public Health; University of South Carolina; Columbia SC USA