1. Center for Cohort Studies, Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
2. Departments of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul, Korea
3. Departments of Occupational and Environmental Medicine, School of Medicine, Kyung Hee University, Seoul, Korea
4. Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, Seoul, Korea