[1] Univ Sydney, Charles Perkins Ctr, Sydney, NSW, Australia
[2] Royal North Shore Hosp, Dept Resp Med, Sydney, NSW, Australia
[3] Royal North Shore Hosp, Dept Resp & Sleep Med, Sydney, NSW, Australia
[4] Univ Sydney, Boden Inst Obes Nutr Exercise & Eating Disorders, Sydney, NSW, Australia
[5] Royal Prince Alfred Hosp, Dept Cardiol, Sydney, NSW, Australia