University of Oxford - Nuffield Department of Population Health, affiliation not provided to SSRN, affiliation not provided to SSRN, Flinders University - Flinders Health and Medical Research Institute, Sir Charles Gairdner Hospital, affiliation not provided to SSRN, University of Pennsylvania, affiliation not provided to SSRN, University of Oxford - Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, affiliation not provided to SSRN, Curtin University - School of Allied Health, Murdoch University, University of Oxford and University of Oxford