[1] Univ Ulsan, Asan Med Ctr, Dept Pulm & Crit Care Med, Coll Med,Clin Res Ctr Chron Obstruct Airway Dis, 88 Olymp Ro 43 Gil, Seoul 05505, South Korea
[2] Chung Ang Univ, Gwangmyeong Hosp, Dept Internal Med, Div Pulm Allergy & Crit Care Med, Gwangmyeong, South Korea
[3] Hallym Univ, Kangdong Sacred Heart Hosp, Dept Internal Med, Div Pulm Allergy & Crit Care Med, Seoul, South Korea
[4] Gangneung Asan Hosp, Dept Pulm Allergy & Crit Care Med, Kangnung, South Korea
[5] Soonchunhyang Univ, Bucheon Hosp, Dept Internal Med, Div Allergy & Resp Med, Bucheon, South Korea
[6] Univ Ulsan, Ulsan Univ Hosp, Dept Internal Med, Div Pulmonol,Coll Med, Ulsan, South Korea
[7] Gachon Univ, Gil Med Ctr, Dept Internal Med, Div Pulmonol & Allergy, Incheon, South Korea
[8] Inha Univ, Dept Occupat & Environm Med, Coll Med, Incheon, South Korea
[9] Korea Res Inst Biosci & Biotechnol, Environm Dis Res Ctr, Daejeon, South Korea
[10] Dankook Univ, Coll Med, Dept Internal Med, Div Resp Dis & Allergy, Cheonan, South Korea