1. School of Medicine, Center for Cohort Studies, Total Healthcare Center, Kangbuk Samsung Hospital Sungkyunkwan University Seoul 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. School of Medicine, Total Healthcare Center, Kangbuk Samsung Hospital Sungkyunkwan University Seoul Korea