1 Department of Diabetes and Endocrinology, University Hospitals Birmingham, Birmingham, B9 5SS, UK; Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK. Electronic address: m.a.karamat@bham.ac.uk.
2 Department of Diabetes and Endocrinology, University Hospitals Birmingham, Birmingham, B9 5SS, UK; School of Health and Life Sciences, University of Aston, Birmingham, UK.
3 Department of Diabetes and Endocrinology, University Hospitals Birmingham, Birmingham, B9 5SS, UK; Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.