[1] Sungkyunkwan Univ, Samsung Med Ctr, Sch Med, Dept Family Med, Seoul 06351, South Korea
[2] Sungkyunkwan Univ, Kangbuk Samsung Hosp, Samsung S&T Med Clin, Sch Med, Seoul 05288, South Korea
[3] Seoul Natl Univ, Bundang Hosp, Dept Family Med, Seongnam Si 13620, Gyeonggi Do, South Korea
[4] Seoul Natl Univ, Coll Med, Dept Family Med, Seoul 03080, South Korea
[5] Seoul Natl Univ Hosp, Dept Family Med, Seoul 03080, South Korea
[6] Seoul Natl Univ, Dept Biomed Sci, Grad Sch, Seoul 03080, South Korea