[1] Sungkyunkwan Univ, Kangbuk Samsung Hosp, Ctr Cohort Studies, Total Healthcare Ctr,Sch Med, Seoul, South Korea
[2] Sungkyunkwan Univ, Kangbuk Samsung Hosp, Dept Neurosurg, Sch Med, Seoul, South Korea
[3] Kyung Hee Univ, Sch Med, Dept Prevent Med, Seoul, South Korea
[4] Kyung Hee Univ, Sch Med, Dept Occupat & Environm Med, Seoul, South Korea
[5] Sungkyunkwan Univ, Kangbuk Samsung Hosp, Total Healthcare Ctr, Sch Med, 67 Sejong Daero, Seoul 04514, South Korea