[1] Univ Portsmouth, Dept Sport & Exercise Sci, Fac Sci, Portsmouth PO1 2ER, Hants, England
[2] Univ Hosp Southampton NHS Fdn Trust, Cyst Fibrosis Unit, Southampton, Hants, England
[3] Univ Portsmouth, Fac Sci, Sch Pharm & Biomed Sci, Portsmouth, Hants, England
[4] Queen Alexandra Hosp, Dept Diabet & Endocrinol, Portsmouth, Hants, England
[5] Southampton Childrens Hosp, Southampton Biomed Res Ctr, Natl Inst Hlth Res, Southampton, Hants, England