1. Department of Medicine, Graduate School, Kyung Hee University, Seoul, Korea.
2. Department of Biomedical Science and Technology, College of Medicine/East-West Medical Research Institute, Kyung Hee University, Seoul, Korea.
3. Department of Preventive Medicine and Public Health, Ajou University School of Medicine, Suwon, Korea.
4. Department of Family Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
5. Department of Preventive Medicine and Public Health, Kyung Hee University School of Medicine, Seoul, Korea.
6. Elderly Frailty Research Center, Department of Family Medicine, College of Medicine, Kyung Hee University, Seoul, Korea.