1. Department of Internal Medicine, Eulji University School of Medicine, Daejeon 35233, Republic of Korea
2. Department of Internal Medicine, Chungnam National University College of Medicine, Daejeon 35015, Republic of Korea
3. Department of Endocrinology, Chungnam National University Sejong Hospital, Sejong 30099, Republic of Korea
4. Department of Internal Medicine, Kangwon National University Hospital, Chuncheon 24289, Republic of Korea