People who develop type 1 diabetes (T1D) in adulthood have an increased risk of cardiovascular disease and death, a study reports.
Patients diagnosed later in life do not have a better prognosis than those diagnosed earlier, say researchers from the Karolinska Institutet in Sweden. Researchers have identified smoking, poor glucose control and obesity as the main risk factors.
The findings are published in the European Heart Journal, highlighting the risks associated with a late T1D diagnosis.
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There is currently limited research into adult-onset T1D, and little is known about prognosis or prognostic factors. Previously referred to as ‘childhood diabetes’, T1D can start at any time in life.
The researchers used data from the Swedish National Diabetes Register and the Total Population Register in Sweden to assess mortality, major adverse cardiovascular events (MACE), and prognostic factors, particularly in adults diagnosed at 40 or older. They identified 10,184 people diagnosed with adult-onset T1D between 2001 and 2020 and compared them with 509,172 matched control participants, as well as 375,523 people with adult-onset type 2 diabetes (T2D).
The participants with adult-onset T1D had a 30 per cent higher risk of experiencing major adverse cardiovascular events
The participants with adult-onset T1D had a 30 per cent higher risk of experiencing MACE, and the risk of death from any cause was 71 per cent higher in this group compared to the control group. Cause-specific mortality, particularly from cardiovascular diseases, non-cardiovascular diseases, cancer, and infections, was also higher in individuals with T1D than in population controls.
Adults who develop T1D later in life have a 33 per cent lower incidence of MACE than individuals who develop T2D in adulthood. However, the risk of death from a diabetic coma or ketoacidosis was higher for individuals with adult-onset T1D compared to those with adult-onset T2D.
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Links to smoking, obesity and poor glucose control
The researchers found the main reasons for the poor prognosis are smoking, overweight/obesity and poor glucose control. In particular, smoking was responsible for 10.7 per cent of deaths and 8.4 per cent of MACE events in individuals with T1D, while poor glycemic control contributed to 10.4 per cent of deaths and 8.8 per cent of MACE events. Overweight and obesity accounted for 19.8 per cent of MACE events.
The study analysis also showed that people who are diagnosed with T1D at age 40 or over are less likely to use assistive devices, such as insulin pumps, to help manage their condition.
Dr Yuxia Wei, a postdoctoral fellow at the Karolinska Institutet and first author of the study, said: ‘These findings underscore the importance of managing these modifiable risk factors to reduce mortality and cardiovascular events in people with T1D.’
Senior author and Associate Professor, Sofia Carlsson, added: ‘We show that the prognosis can be significantly improved by preventing smoking and obesity and improving glucose control, not least in people diagnosed at older ages.’
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Reference: Y Wei, et al. Adult-onset type 1 diabetes: predictors of major cardiovascular events and mortality. 2025. https://doi.org/10.1093/eurheartj/ehaf304
