[1] Sungkyunkwan Univ, Samsung Med Ctr, Dept Med, Sch Med, Seoul 06351, South Korea
[2] Sungkyunkwan Univ, Dept Clin Res Design & Evaluat, SAIHST, 81 Irwon Ro, Seoul 06351, South Korea
[3] Samsung Med Ctr, Ctr Clin Epidemiol, Seoul 06351, South Korea
[4] Samsung Med Ctr, Ctr Hlth Promot, Seoul 06351, South Korea
[5] Kangbuk Samsung Hosp, Ctr Total Hlth Studies, Seoul 03181, South Korea
[6] Johns Hopkins Med Inst, Dept Epidemiol, Baltimore, MD 21287 USA
[7] Johns Hopkins Med Inst, Dept Med, Baltimore, MD 21287 USA
[8] Johns Hopkins Med Inst, Welch Ctr Prevent Epidemiol & Clin Res, Baltimore, MD 21287 USA