1 School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, England; Sheffield Adult Cystic Fibrosis Centre, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England. Electronic address: z.hoo@sheffield.ac.uk.
2 Wolfson Adult Cystic Fibrosis Centre, Nottingham University Hospitals NHS Trust, Nottingham, England.
3 York Hull Adult Cystic Fibrosis Centre, York Teaching Hospital NHS Foundation Trust, York, England; School of Science, Technology and Health, York St John University, York, England.
4 School of Health Sciences, University of Manchester, Manchester, England.
5 Sheffield Adult Cystic Fibrosis Centre, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England.
6 School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, England; Sheffield Adult Cystic Fibrosis Centre, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England.