Specialist in diabetes research Professor Kathleen Gillespie describes the under-recognised incidence of type 1 diabetes among adults, and how nurses in the community can help support research to identify those at risk and offer early intervention
Type 1 diabetes in adults – an under-investigated group
Type 1 diabetes affects around 1 in 250 individuals. It is an autoimmune condition, in which a person’s immune system attacks their own healthy tissues by mistake – in type 1 diabetes this results in immune cells (T cells) killing the insulin-producing beta cells in the pancreas.
Insulin is essential for controlling blood glucose levels; when 70-80% of beta cells in the pancreas have been killed, blood glucose levels rise, resulting in the appearance of symptoms and ultimately in the diagnosis of diabetes.
The symptoms of diabetes are described by Diabetes UK as the ‘4Ts’; toilet, thirst, tired and thinner. Type 1 diabetes is treated with insulin and the methods of delivering insulin have improved markedly over the last decade.
There is a peak in incidence of type 1 diabetes in early adolescence, at 11-12 years of age, and as a consequence type 1 diabetes is often seen as a condition of childhood.
However, we know that more than half of type 1 diabetes cases develop in adulthood. This can lead to difficulties in diagnosis, particularly in those presenting in mid-life where some individuals with autoimmune type 1 diabetes are misdiagnosed with type 2 diabetes. This risk is increasing as the age at onset of type 2 diabetes decreases.
Key to diagnosis is the presence of markers of the autoimmune process, termed autoantibodies, in type 1 diabetes. There are five different types: autoantibodies to insulin (IAA); glutamic acid decarboxylase (GADA); islet antigen-2 (IA-2A); zinc transporter 8 (ZnT8A); and more recently tetraspanin 7 (Tspan7A).
Recently NICE guidelines were updated to recommend measuring autoantibodies in adults to aid diagnosis and the UK Type 1 Diabetes Research Consortium have led on recent guidelines on diagnosing type 1 diabetes in adults.
Type 1 diabetes can be predicted
The diabetes-specific autoantibodies described above are usually present in the blood many years before diagnosis of type 1 diabetes. Children with two or more autoantibodies, when they are under 5 years old, have >80% risk of developing symptoms of diabetes by the age of 20 years. Tests for these markers have improved and it is now possible to identify who is at risk of developing type 1 diabetes in the future by testing tiny blood samples which can be collected by post.
In 2018, a clinical trial showed that an immunotherapy, the anti-T cell agent Teplizumab, successfully delayed the onset of type 1 diabetes in individuals with multiple autoantibodies. This drug has been approved by the FDA in the USA for use in ‘at risk’ individuals leading to an international focus on identifying individuals at risk for additional clinical trials and potential therapy.
However, while risk in children has been well studied, little is understood about risk prediction in adults. Future screening for autoantibodies in adults requires the natural history of the condition to be understood, so that those with autoantibodies can be given accurate information of risk.
The Type 1 diabetes Risk in Adults (T1DRA) study was therefore set up by a research team at the University of Bristol. The aim is to recruit and test for diabetes-specific autoantibodies in 20,000 adults. All recruitment is online through the T1DRA study website. Participants between 18 and 70 years can consent online and will be sent capillary blood kits to collect the sample at home. Video instructions are provided. The samples are tested in the Alistair Williams Antibody Facility and participants are notified of their results. Those positive for one or more autoantibody are invited for annual follow up.
How can nurses in the community support the research?
GPs and community nurses can help by asking patients and colleagues if they are interested in research, and if they’re aware that type 1 diabetes can be accurately predicted by a simple blood test through the online T1DRA study. This prevents diagnosis of diabetes in an emergency when patients often go into diabetic ketoacidosis.
To date almost 7,000 people have participated; these are mostly White females so the study welcomes male participants and those from diverse backgrounds. The T1DRA study team are hoping to increase the diversity of participants in T1DRA so that risk of type 1 diabetes in all communities is better understood.
All help is very much appreciated by the research team.
Professor Kathleen Gillespie is Professor Molecular Medicine at the University of Bristol
