1. Department of Family Medicine, Hallym University Dongtan Sacred Heart Hospital, Hwaseong, Republic of Korea (D.L.).
2. Department of Family Medicine/Supportive Care Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea (I.Y.C., D.W.S.).
3. Department of Clinical Research Design and Evaluation, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Republic of Korea (I.Y.C., W.H.C., H.L.C., D.W.S.).
4. Department of Physical and Rehabilitation Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea (W.H.C.).
5. Department of Family Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Republic of Korea (J.E.Y.).
6. Department of Family Medicine/Executive Healthcare Clinic, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea (H.L.C.).
7. Center for Cohort Studies, Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea (J.P.).
8. Department of Statistics and Actuarial Science, Soongsil University, Seoul, Republic of Korea (K.H.).