1. From the Center for Cohort Studies, Total Healthcare Center (Y.C., K.E.Y., H.-S.J., C.-W.K., S.R.), Department of Occupational and Environmental Medicine (Y.C., S.R.), Department of Laboratory Medicine (M.-J.K.), and Department of Family Medicine (E.S.), Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, Seoul, Korea.