1. Department of Diabetes and Endocrinology, Lister Hospital, East and North Hertfordshire NHS Foundation Trust, Stevenage SG1 4AB, United Kingdom
2. Department of Diabetes and Endocrinology, Great Western Hospitals NHS Foundation Trust , Swindon SN3 6BB, United Kingdom
3. Department of Pathology, Great Western Hospitals NHS Foundation Trust , Swindon SN3 6BB, United Kingdom