1. Deparment of Internal Medicine, Seoul National University Hospital Healthcare System Gangnam Center, Seoul, Korea.
2. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Chungnam National University College of Medicine, Daejeon, Korea.
4. Center for Gastric Cancer, National Cancer Center, Goyang, Korea.
5. Department of Internal Medicine, Hallym University College of Medicine, Chuncheon, Korea.
6. Department of Internal Medicine, Ewha Womans University College of Medicine, Seoul, Korea.
7. Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu, Korea.
8. Division of Gastroenterology, Department of Internal Medicine, Kyungpook National University Chilgok Hospital, Daegu, Korea.
9. Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea.