Type 1 diabetes could be more common in adults than previously believed, according to new Diabetes UK-funded research.

Scientists at the University of Exeter Medical School have found that more than 40% of type 1 diabetes cases could occur after the age of 30.

Type 1 diabetes could be harder to recognise in adults, because far more people develop type 2 diabetes in later life. According to this research, type 2 diabetes accounts for 96 per cent of diabetes cases in people between 31 and 60 years of age. 

It’s important to distinguish between type 1 or type 2 diabetes, as treatments are different for both conditions, and a misdiagnosis could be life threatening. Previous Exeter research found that, on average, it took a year for those with type 1 diabetes who had been misdiagnosed to be given the necessary insulin therapy. 

In type 1 diabetes, insulin-producing beta cells are destroyed, so people need to take insulin to control their blood glucose levels. With type 2 diabetes, the body stops responding properly to insulin, which can be initially treated with diet and tablets.

 

The study, published in the Lancet Diabetes and Endocrinology, is the first to use a new genetic technique to find type 1 diabetes in adults. They studied genetic information from nearly 380,000 people in the UK Biobank. Using key type 1 diabetes genes to calculate each person’s risk of having the condition, they found that type 1 occurred relatively evenly across the first six decades of life. 
 
Dr Richard Oram, a Diabetes UK Harry Keen fellow involved in the research, said: “Diabetes textbooks for doctors say that Type 1 diabetes is a childhood illness. But our study shows that it is prevalent throughout life. The assumption among many doctors is that adults presenting with the symptoms of diabetes will have Type 2 but this misconception can lead to misdiagnosis with potentially serious consequences. 

“This study should raise awareness that Type 1 diabetes occurs throughout adulthood and should be considered as a diagnosis.”

Dr Emily Burns, Acting Head of Research Communications at Diabetes UK, said: “Type 1 diabetes is much more common than Type 2 diabetes in children and young adults. With increasing age, Type 2 diabetes becomes more common, making Type 1 diabetes less easy to identify. 

“While more research is needed to understand the realities of misdiagnosis, we’d ask healthcare professionals to have this insight in mind: don’t rule out Type 1 diabetes after the age of 30.”

The study was funded by the Wellcome Trust and Diabetes UK.