[1] Univ Leicester, Sch Med, Leicester LE1 7RH, Leics, England
[2] Rmit Univ, Sch Hlth & Biomed Sci, Melbourne, Vic, Australia
[3] United Lincolnshire Hosp NHS Trust, Pilgrim Hosp, Dept Endocrinol & Metab, Boston PE21 9QS, England
[4] Lancashire Teaching Hosp NHS Trust, Dept Endocrinol & Metab, Sharoe Green Lane, Preston PR2 9HT, Lancs, England
[5] Manchester Metropolitan Univ, Fac Sci, Manchester M15 6BH, Lancs, England
[6] Univ Manchester, Fac Biol Med & Hlth, Manchester M13 9PL, Lancs, England