1. Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.
2. Department of Internal Medicine and Cardiovascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Division of Biostatistics, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA.
4. Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Korea.
5. Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Institute of Aging, Seoul National University, Seoul, Korea.