[1] Univ York, Dept Hlth Sci, York YO10 5DD, N Yorkshire, England
[2] Univ York, Ctr Reviews & Disseminat, York YO10 5DD, N Yorkshire, England
[3] Univ York, Dept Econ & Related Studies, York YO10 5DD, N Yorkshire, England
[4] Manchester Royal Infirm, Dept Diabet Med, Manchester, Lancs, England
[5] Univ Warwick, Dept Biol Sci, Coventry CV4 7AL, W Midlands, England
[6] Univ Warwick, Dept Primary Care, Coventry CV4 7AL, W Midlands, England
[7] Univ Hosp Coventry, Dept Gen & Vasc Surg, Coventry, W Midlands, England
[8] Univ Hosp Warwickshire, Dept Gen & Vasc Surg, Coventry, W Midlands, England
[9] Univ Hosp Warwickshire, Dept Gen Med, Coventry, W Midlands, England
[10] Univ Hosp Coventry, Dept Gen Med, Coventry, W Midlands, England
[11] Univ Hosp Coventry, Dept Pathol, Coventry, W Midlands, England
[12] Univ Hosp Warwickshire, Dept Pathol, Coventry, W Midlands, England