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Professor Colin Dayan

Professor Colin Dayan

Professor Colin Dayan
BA(Oxon.), MBBS(London), MRCP (FRCP), PhD(London)

Professor of Diabetes and Endocrinology

Area of research

Type 1 Diabetes and Thyroid Research

Diabetes and Metabolism,
Learning and Research, Second Floor BS10 5NB
(See a map)

+44 (0) 117 928 3553
+44 (0) 117 331 3121


Activities / Findings

Our research group has two sections:

Thyroid Research Group

The Cardiff Thyroid Research Group has been at the forefront of thyroid research for over 25 years with the work of many colleagues including Reg Hall, John Lazarus and Marian Ludgate. Our current focus is on Thyroid Eye Disease (Graves’ Orbitopathy, GO) and the mechanisms underlying this disfiguring and distressing condition, including retro-orbital pre-adipocyte function and the effects of the microbiome. We also work closely with ophthalmology colleagues and as part of TEAMeD and the EUGOGO group to conduct clinical studies to improve therapies and implement measures to improve outcomes.

The Thyroid Research Group also conducts large scale epidemiological, genetic and data linkage studies to define the effects of changes in thyroid hormone levels across the population, to study the effects of thyroid hormone replacement and the long-term outcomes of thyroid disease including thyroid disease in pregnancy.

Immunotherapy of Type 1 Diabetes

Our group is committed to finding low-risk immunotherapies able to preserve beta cell function in type 1 diabetes and introduce these therapies into clinical care. We collaborate with colleagues across the UK in the Type 1 Diabetes Immunotherapy Consortium to conduct clinical trials in adults and children with new-onset type 1 diabetes and develop new approaches to beta cell preservation. Studies range from first-in-man to phase III. In this area we work closely with partners including Diabetes UK, the Juvenile Diabetes Research Foundation (JDRF), the Diabetes Research Unit Wales, SAIL and the University of Bristol. We are developing large scale data-linkage projects to define the outcomes for patients with type 1 diabetes and the potential benefits of beta cell preservation. 

Scientific contributions of our research group include:

  • First to clone and define antigen specific T cells from the target organ in Graves disease, demonstrating a highly focused but multi-antigenic response
  • First large RCT of diet vs diet and exercise in new-onset type 2 diabetes – indicating that diet alone is as effective as diet and exercise for glycaemic control and weight reduction.
  • Set up of the UK Type 1 Diabetes Immunotherapy Consortium to coordinate immunotherapy trials in new-onset type 1 diabetes across the UK: increased recruitment into trials 10-fold; two multicentre studies fully recruited to date and to time/ahead of time with 4 in set-up.
  • Demonstration of the safety and potential for efficacy of peptide-based immunotherapy for type 1 diabetes in man including two first-in-man studies.
  • Development of novel platforms for antigen specific immunotherapy and monitoring in type 1 diabetes including microneedle delivery and direct lymph node sampling in humans.
  • Development of data-linkage cohorts with SAIL (Farr Institute) covering subjects with thyroid disease and all children in Wales with type 1 diabetes (Brecon cohort): demonstration that variation in thyroid function even within the laboratory reference range affects a large range of clinical outcomes including miscarriage, obesity and fracture and that there is a persistent 4 fold excess in admission rates for children diagnosed with type 1 diabetes in childhood.
  • Description of the genetic architecture underlying thyroid function using next generation sequencing and its application in Mendelian Randomisation to demonstrate an effect of fat mass on circulating T3 levels in children.


Recent publications

View complete publications list in the University of Bristol publications system

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