1. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
3. Department of Neuropsychiatry, Seoul National University Bundang Hospital, Seongnam, Korea.
4. Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
5. Department of Preventive Medicine, Ajou University School of Medicine, Suwon, Korea.