[1] Gachon Univ, Dept Occupat & Environm Med, Gil Med Ctr, Inchon, South Korea
[2] Yonsei Univ, Dept Prevent Med, Coll Med, Seoul, South Korea
[3] Ajou Univ, Dept Humanities & Social Med, Sch Med, Suwon, South Korea
[4] Kwandong Univ, Cheil Gen Hosp, Dept Med Cardiol, Coll Med, Seoul, South Korea