1Department of Occupational and Environmental Medicine, Soonchunhyang University Gumi Hospital, 179, Gongdan 1-dong, Gumi-si, Gyeongbuk 730-706, South Korea
2Department of Preventive Medicine, Soonchunhyang University School of Medicine, Cheonan, 23-20, Bongmyung-dong, Cheonan-si, Choongchungnam-do 330-721, South Korea JFIF d d Ducky d qhttp://ns.adobe.com/xap/1.0/