1Department of Family Medicine, University of Ulsan College of Medicine, Seoul, Korea. youngkim@amc.seoul.kr
2Department of Family Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
3Department of Family Medicine, Keimyung University College of Medicine, Daegu, Korea.
4Department of Family Medicine, Pusan National University School of Medicine, Busan, Korea. JFIF d d Ducky d qhttp://ns.adobe.com/xap/1.0/