1. Department of Internal Medicine, College of Medicine, Pochon CHA University, Sungnam, Korea.
2. Department of Preventive Medicine, College of Medicine, Pochon CHA University, Sungnam, Korea.
3. Department of Thoracic and Cardiovascular Surgery, College of Medicine, Pochon CHA University, Sungnam, Korea.
4. Department of Internal Medicine, College of Medicine, Seoul National University, Seoul, Korea.
5. Department of Internal Medicine, University of New Mexico, Albuquerque, USA.
6. Department of Internal Medicine, McMaster University, Hamilton, Canada.
7. Department of Internal Medicine, University of Insubria, Varese, Italy.