[1] Univ Newcastle, Sch Med & Publ Hlth, Ctr Asthma & Resp Dis, Callaghan, NSW 2308, Australia
[2] John Hunter Hosp, Dept Resp & Sleep Med, 2 Lookout Rd, Newcastle, NSW 2305, Australia
[3] Univ New S Wales, Inflammat & Infect Res Ctr, Fac Med, POB 1, Kensington, NSW 2033, Australia
[4] Univ New S Wales, Prince Wales Hosp, Fac Med, Sch Clin, POB 1, Kensington, NSW 2033, Australia
[5] Prince Wales Hosp, Dept Resp Med, Randwick, NSW 2031, Australia
[6] Univ Hong Kong, Dept Med, Hong Kong, Hong Kong, Peoples R China
[7] Univ Hong Kong, Dept Pharmacol & Pharm, Hong Kong, Hong Kong, Peoples R China
[8] Univ Hong Kong, Dept Med & Therapeut, Hong Kong, Hong Kong, Peoples R China
[9] Univ Colorado Colorado Springs, Helen & Arthur Johnson Beth El Coll Nursing & Hlt, Colorado Springs, CO USA
[10] Natl Univ Singapore Hosp, Dept Med, Singapore 117548, Singapore