1. Department of Family Medicine, Seoul Medical Center, Seoul, Korea
2. School of Medicine and Pharmacology, The University of Western Australia, Crawley, Australia
3. Environmental Health Center, Korea University Anam Hospital, Seoul, Korea
4. Department of Family Medicine, College of Medicine, Hallym University, Chuncheon, Korea
5. Institute of Geriatric Medicine, Incheon Eun-Hye Hospital, Incheon, Korea
6. Department of Psychiatry, National Medical Center, Seoul, Korea
7. Department of Rheumatology, Chung-Ang University College of Medicine, Seoul, Korea
8. Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
9. Elderly Frailty Research Center, Department of Family Medicine, College of Medicine, Kyung Hee University, Seoul, Korea