[1] Univ Ulsan, Coll Med, Dept Internal Med, Asan Med Ctr, 88,Olymp Ro 43 Gil, Seoul 05505, South Korea
[2] Univ Ulsan, Coll Med, Dept Surg, Asan Med Ctr, Seoul, South Korea
[3] Univ Ulsan, Coll Med, Dept Clin Epidemiol & Biostat, Asan Med Ctr, Seoul, South Korea
[4] Univ Ulsan, Coll Med, Dept Psychiat, Asan Med Ctr, Seoul, South Korea