1. Department of Preventive Medicine Yonsei University College of Medicine Seoul Republic of Korea
2. Department of Internal Medicine Yonsei University College of Medicine Seoul Republic of Korea
3. Institute of Gastroenterology Yonsei University College of Medicine Seoul Republic of Korea
4. Yonsei Liver Center, Severance Hospital Yonsei University Health System Seoul Republic of Korea
5. Institute for Occupational Health Yonsei University College of Medicine Seoul Republic of Korea