1. Department of Public Health, Graduate School, Korea University, Seoul, Korea.
2. Services Department, Medical Library, Korea University, Seoul, Korea.
3. Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea.
4. Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
5. Division of Cardiology, Department of Internal Medicine, Dongguk University College of Medicine, Ilsan Hospital, Dongguk University Medical Center, Ilsan, Korea.
6. Division of Respiratory Allergy and Critical Care Medicine, Department of Internal Medicine, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.
7. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
8. Department of Healthcare and Medicine for Unified Korea, Korea University College of Medicine, Seoul, Korea.
9. Department of Preventive Medicine, Konyang University College of Medicine, Daejeon, Korea.