[1] Guys Hosp, Guys & St Thomas NHS Fdn Trust, Dept Endocrinol & Diabet, London SE1 9RT, England
[2] Univ Kent, Math Inst, Canterbury CT2 7NF, Kent, England
[3] Univ Naples Federico II, Dept Internal Med & Cardiovasc Sci, I-80131 Naples, Italy
[4] Aarhus Univ Hosp, DK-8000 Aarhus, Denmark
[5] Sahlgrens Univ Hosp, Dept Endocrinol, SE-41345 Gothenburg, Sweden