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 per cent 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.
Helen Philbin, from Torquay, was diagnosed with type 2 diabetes and prescribed metformin. Her symptoms did not improve, however; she continued to lose weight and had regular bouts of vomiting. After taking part in research in Exeter, she discovered she had type 1 diabetes and had been on the wrong medication for a year. She said: “I’m so pleased I was invited to take part in the trial and I got the right diagnosis. It’s such a relief and it’s made such a difference.”
New genetic test
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.”
Type 1 more common in children
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.