1. Aging and Health Research Center, National Yang Ming University, Taipei, Taiwan.
2. Institute of Public Health, National Yang Ming University, Taipei, Taiwan.
3. Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan.
4. Department of Family Medicine, Taipei Veterans General Hospital Yuanshan Branch, I-Lan, Taiwan.
5. Department of Family Medicine, Kyung Hee University School of Medicine, Seoul, South Korea.