1. 1Department of Family Medicine, Seoul National University Hospital, Seoul National University School of Medicine, Seoul, Korea.
2. 2Department of Statistics and Actuarial Science, Soongsil University, Seoul, Korea.
3. 3Department of Biomedicine & Health Science, The Catholic University of Korea, Seoul, Korea.
4. 4Department of Family Medicine, Hallym University Dongtan Sacred Heart Hospital, Gyeonggi-do, Korea.
5. 5Department of Family Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. 6Department of Family Medicine/Supportive Care Center, Samsung Medical Center, Seoul, Korea.
7. 7Department of Clinical Research Design & Evaluation, Samsung Advanced Institute for Health Science & Technology (SAIHST), Sungkyunkwan University, Seoul, Korea.
8. 8Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
9. 9Department of Epidemiology, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas.