[1] Univ British Columbia, Ctr Heart Lung Innovat, St Pauls Hosp, Vancouver, BC, Canada
[2] Univ British Columbia, Dept Med, Vancouver, BC, Canada
[3] Univ Occupat & Environm Hlth, Kitakyushu, Fukuoka, Japan
[4] Zhejiang Univ, Sch Med, Resp Dept, Affiliated Hosp 1, Hangzhou, Zhejiang, Peoples R China