NEW YORK (Reuters) – Despite popular belief that type-1 diabetes (T1D) is a disease that starts in childhood, its onset in adults is substantial, researchers report.
A review of population-based studies looking at adult-onset T1D revealed incidence rates as high as 92.9 per 100,000 in certain groups of adults, according to findingsin Diabetes Care.
“In this systematic review, we show that the incidence of type 1 diabetes in adulthood is substantial and highlight the pressing need to better distinguish type-1 from type-2 diabetes in adults so that we may better assess and respond to the true burden of type-1 diabetes in adults,” said Dr. Jessica Harding of Emory University, Atlanta.
“Among studies that reported type-1 diabetes by age group, there was no obvious correlation between age and incidence – in other words, we did not see that as age increased, incidence of type-1 diabetes decreased, as we may have hypothesized,” she told Reuters Health by email. “Of course, more studies are needed to confirm this finding.”
The finding ought to impact care, Dr. Harding said.
“In 2021, the American Diabetes Association and the European Association for the Study of Diabetes published a joint statement recommending the use of islet antibodies, in conjunction with clinical features and a C-peptide test (particularly after greater than three years’ diabetes duration), to distinguish T1D from T2D in adults with suspected T1D,” she added. “We hope that the findings of our study, indicating a substantial burden of adult-onset type-1 diabetes, will raise awareness and prompt recognition of adult-onset type-1 diabetes to facilitate appropriate early insulin therapy, which may improve long-term prognosis.”
To take a closer look at the incidence of adult onset T1D, Dr. Harding and her colleagues scoured the medical literature for studies reporting on the topic. The team identified 1,374 references, of which 46 were included in their analysis.
The researchers concluded that there was a “paucity” of data on adult-onset T1D, particularly in low- and middle-income countries. The incidence rates appeared to vary depending on geographic area, with the highest incidence in Nordic countries and the lowest in Asian nations.
Overall, adult-onset T1D was higher in men than in women. The team could not determine whether there were any age-related trends or whether the incidence had changed over time.
Rates reported in the studies varied widely. For example, a study conducted in Sweden found an incidence rate of 6.3 per 100, 000 in women aged 30-34, while a U.S. Navy study reported a rate of 92.9 per 100,000 in women of the same age.
“There is a pressing need for more well-designed and large-scale epidemiological studies, including biomarker data, to appreciate the true burden of type-1 diabetes in different parts of the world, especially given the paucity of available data from low- to middle-income countries,” Dr. Harding said.
The new study show that new-onset T1D is not only a disease of childhood, said Dr. Esra Karslioglu French, an endocrinologist and a clinical associate professor of medicine at the University of Pittsburgh School of Medicine and the endocrine medical director at UPMC.
“Clinicians need to be aware of this data and have type-1 diabetes as a differential diagnosis in adults as well,” Dr. French told Reuters Health by email. “The management of type-1 and type-2 diabetes are very different.”
“In type-1 DM, the pancreas almost does not secrete any insulin, so patients need to be started on an intensive insulin regimen as soon as possible to prevent ... diabetic ketoacidosis,” Dr. French said. “Whereas in type-2 DM, there is less urgency to the management; most patients can be managed by lifestyle changes and pills first, then transition to insulin later if needed.”
“This paper will hopefully help us to decrease misdiagnosis of type-1 DM in adults,” he added.
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