1. Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine
2. Departments of Preventive Medicine, School of Medicine, Kyung Hee University
3. Ewha Institute of Convergence Medicine, Ewha Womans University Mokdong Hospital
4. Department of Occupational and Environment Medicine, College of Medicine, Ewha Womans University
5. Department of Internal Medicine, Veterans Healthcare Service Medical Center
6. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kyung Hee University School of Medicine
7. Department of Anesthesiology and Pain Medicine, Kyung Hee University Hospital
8. Departments of Occupational and Environmental Medicine, School of Medicine, Kyung Hee University