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