[1] Wythenshawe Hosp, Adult Cyst Fibrosis Ctr, Manchester M23 9LT, Lancs, England
[2] Royal Liverpool Univ Hosp, Liverpool, Merseyside, England
[3] Univ Edinburgh, Sch Med, Edinburgh, Midlothian, Scotland
[4] Cardiothorac CF Ctr, Reg Adult Cyst Fibrosis Unit, Liverpool, Merseyside, England