About the Authors

Jodie L. Simpson

jodie.simpson@newcastle.edu.au

Affiliation Centre for Asthma and Respiratory Diseases and Hunter Medical Research Institute, Faculty of Health and Medicine, The University of Newcastle, Callaghan, New South Wales, Australia

Heather Powell

Affiliation Department of Respiratory and Sleep Medicine, Hunter New England Area Health Service, Newcastle, New South Wales, Australia

Katherine J. Baines

Affiliation Centre for Asthma and Respiratory Diseases and Hunter Medical Research Institute, Faculty of Health and Medicine, The University of Newcastle, Callaghan, New South Wales, Australia

David Milne

Affiliation Auckland District Health Board, Auckland, New Zealand

Harvey O. Coxson

Affiliation Department of Radiology and James Hogg Research Centre, University of British Columbia, Vancouver, Canada

Philip M. Hansbro

Affiliation Centre for Asthma and Respiratory Diseases and Hunter Medical Research Institute, Faculty of Health and Medicine, The University of Newcastle, Callaghan, New South Wales, Australia

Peter G. Gibson

Affiliations Centre for Asthma and Respiratory Diseases and Hunter Medical Research Institute, Faculty of Health and Medicine, The University of Newcastle, Callaghan, New South Wales, Australia, Department of Respiratory and Sleep Medicine, Hunter New England Area Health Service, Newcastle, New South Wales, Australia

Competing Interests

Research was funded by the National Health and Medical Research Council of Australia with project grant id 455508. JS salary is supported by the Australian Respiratory Council. KB salary is supported by the University of Newcastle. HO Coxson has received an honorarium for serving on the steering committee for the ECLIPSE project for GSK. In addition HC was the co-investigator on two multi-center studies sponsored by GSK and has received travel expenses to attend meetings related to the project. HC has a contract service agreement with Spiration Inc to measure changes in lung volume in subjects with severe emphysema. HC has received a fee for speaking at a conference and related travel expenses from AstraZeneca (Australia). There is no financial relationship between any industry and the current study. PGG reports grants from NHMRC, during the conduct of the study; personal fees from GlaxoSmithkline, AstraZeneca, Boerhinger Ingelheim, outside the submitted work. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: JLS PGG. Performed the experiments: JLS KJB DM HOC PMH PGG. Analyzed the data: JLS HP. Contributed reagents/materials/analysis tools: JLS DM HOC PGG. Wrote the paper: JLS HP PGG.