1. Korea University College of Medicine; Seoul Korea
2. Division of Rheumatology; Department of Internal Medicine; Korea University Guro Hospital; Seoul Korea
3. Graduate School of Public Health; Yonsei University; Seoul Korea
4. Institute for Occupational Health, Yonsei University College of Medicine; Seoul Korea
5. Division of Rheumatology; Department of Internal Medicine; Korea University Ansan Hospital; Ansan-si Gyeonggi-do, Seoul, Korea