1. Department of Clinical and Experimental Medicine, University of Surrey, Guildford, Surrey, U.K.
2. The Centre for Diabetes, Endocrinology and Research (CEDAR), Royal Surrey County Hospital, Guildford, Surrey, U.K.
3. Regional Oesophagogastric Unit/Gastrointestinal Surgery, Royal Surrey County Hospital, Guildford, Surrey, U.K.
4. Division of Healthcare Delivery Science/Center for Healthcare Innovation and Delivery Science (CHIDS), Department of Population Health, New York University, Langone Medical Centre, New York, NY
5. Royal College of General Practitioners Research and Surveillance Centre, London, U.K.