In one of the largest global studies of its kind, a multi-institution collaborative of researchers led by Emory University found that onset of type 1 diabetes, once known as juvenile diabetes, is much higher among adults than previously believed.
The investigators reviewed all published studies between 1990 and 2021 and found that there was a significant burden of newly diagnosed type 1 diabetes among adults.
In surveying global patterns of the disease, researchers found that prevalence varied considerably by geographic region, with rates of new cases of adult-onset type 1 diabetes lowest in Asian countries and highest in Nordic countries — a finding that is consistent with other research on children and adolescents with this disease.
The study, published in the journal Diabetes Care, also found that men are more likely than women to be diagnosed with. adult-onset type 1 diabetes and a significant number present late in life.
Jessica Harding, assistant professor at Emory’s School of Medicine and lead investigator of the study, says the findings upend conventional thinking that type 1 diabetes rarely begins in adulthood.
“We also saw no clear relationship between age and the rates of type 1 diabetes presenting in adults — in other words, the number of new cases does not appear to decline with increasing age,” Harding says.
The researchers looked at 46 studies from 32 countries and regions and found there to be a more than 30-fold difference in the annual rates of type 1 diabetes presenting in adults, which ranged from less than 1 per 100,000 in China to more than 30 per 100,000 in Sweden.
The research team also developed an index to evaluate the quality of existing studies, including the incorporation of biomarkers to ascertain diagnosis of type 1 diabetes, which, Harding hopes, will help improve the design of future studies.
Harding says there is a pressing need for more well-designed studies “to appreciate the true burden of type 1 diabetes in different parts of the world given the paucity of data from low-to-middle income countries.”
Type 1 diabetes is characterized by the body making little to no insulin, which could explain why it was once also labeled as insulin-dependent diabetes. The World Health Organization estimates that type 1 diabetes, while significantly lower in incidence than the more common type 2 diabetes, affects 9 million people worldwide.
Participating institutions in the study spanned the globe and include the Chinese University of Hong Kong, University of Sydney, Exeter University, Central South University, University of Washington, Baker Heart and Diabetes Institute and the International Diabetes Federation.
The study was initiated as part of the International Diabetes Federation Diabetes Atlas (10th edition) and highlights of this study can be found in the Atlas. The study comes in a year that marks the centenary of insulin first being injected into a person, a 14-year-old boy, to treat diabetes.