Type 2 diabetes has traditionally been a disease that has developed mostly in middle-aged and older adults. But new research from the USA to be presented at the Annual Meeting of The European Association for the Study of Diabetes (EASD) in Milan, Italy (Sept 28 – Oct 2) shows a sharp increase in the rate of new cases of type 2 diabetes since the turn of the century, which has continued to accelerate in recent years. The study is by Dr Tessa Crume, Colorado School of Public Health, Aurora, CO, USA, and colleagues.
Youth onset type 1 and type 2 diabetes incidence in youth have increased steadily in the USA for several decades, resulting in significant burden of diabetes related morbidity and mortality. In this new study, the authors examined long-term trends in youth onset type 1 and type 2 diabetes in Colorado, USA between 2002-2023.
The Colorado Diabetes Registry has conducted continuous, population-level, annual analysis of diabetes incidence among youth aged under 20 years since 2002 across health systems in the state using diagnosis codes, laboratory results, and medication data. Eligible participants were non-military, non-institutionalised individuals residing in Colorado at the time of diagnosis. Population denominators were obtained from census data. Statistical modelling was used to estimate trends over time. Incidence rates were calculated per 100,000 youth aged <20 years for type 1 diabetes and per 100,000 youth aged 10-19 years for type 2 diabetes (since cases of type 2 diabetes in children under 10 years are extremely rare).
Between 2002 and 2023, 8,094 children and teens under 20 were newly diagnosed with type 1 diabetes and 1,560 youth aged 10-19 years were diagnosed with new-onset type 2 diabetes. The incidence of type 1 diabetes increased slightly from 25.07 per 100,000 in 2002 to 27.39 per 100,000 in 2023. There was a stable trend of incident type 1 diabetes between 2002-2014 (annual percentage change [APC]=0.66%) followed by an increasing trend between 2015-2023 (APC=2.62%).
However, the incidence of type 2 diabetes among youth aged 10-19 years increased almost 10-fold from 2.37 per 100,000 in 2002 to 22.30 per 100,000 in 2023. The incidence of type 2 diabetes increased by 3.8% across the whole period 2002-2023; by 2.92% annually between 2002-2013, and even more sharply by 4.72% annually between 2014-2023.
The authors say: "Across this period of over two decades since the turn of the century, new-onset type 2 diabetes incidence in youth increased by almost 10-fold, compared with type 1 diabetes incidence that only slightly increased. These findings document an expanding population of youth at risk for diabetes-related complications across the life-course and underscore the importance of sustained long-term surveillance."
Dr Crume explain: "A generation ago, type 2 diabetes in a teenager was so rare that many paediatric clinicians could go through much of their career without seeing a case; it was a disease of middle age. In Colorado, we have now watched it rise nearly tenfold in young people in just two decades, and the increase is accelerating rather than slowing. This is not a local anomaly: in the US-based SEARCH for Diabetes in Youth study, youth type 2 diabetes is climbing more than twice as fast as type 1, and among older teenagers new type 2 cases have already overtaken type 1. A disease we once considered exclusively adult only, type 2 diabetes, is now outpacing the classic form of childhood diabetes – type 1."
The authors explain rising obesity rates across all children means it is no longer possible to reliably tell type 1 from type 2 diabetes in a newly diagnosed teenager; the conditions increasingly overlap in how they present clinically. A teenager with a high BMI presenting with high blood sugar could have either type 1 or type 2 diabetes. Distinguishing them requires testing for diabetes autoantibodies, which mark the autoimmune process of type 1, and for insulin resistance, which characterises type 2. That classification determines treatment, so the diagnostic pathway has to be established to ensure the correct diagnosis. Dr Crume says: "The services needed, then, are not only about capacity to treat a growing number of young people; they are about ensuring that every child with new-onset diabetes receives proper autoantibody and metabolic testing rather than being classified on impression."
She explains that doctors are increasingly less surprised to see type 2 diabetes in young people and teenagers. "Twenty years ago a pediatric endocrinologist might have paused at a teenager with type 2 diabetes; today it is a routine and growing part of their caseload. Where surprise does persist is in primary care and in the community, where type 2 diabetes in a child can still be underestimated or missed because the old assumption that this is an adult disease. So the risk is not that clinicians are shocked; it is that a young person's diabetes is overlooked or treated improperly."
And she concludes with a stark warning of the tidal wave of health problems coming for these and other young people. "The danger is considerable, and it is why these trends matter so much. Type 2 diabetes in a young person is a more aggressive disease than the same diagnosis in a middle-aged adult. The insulin-producing cells of the pancreas decline faster, blood sugar is harder to control, and complications affecting the kidneys, eyes, nerves, and heart can appear within just a few years rather than decades. A child diagnosed at 14 faces the prospect of these complications in early adulthood, and youth-onset type 2 diabetes is associated with a shortened life expectancy.
"While newly diagnosed type 2 diabetes can sometimes be pushed into remission, the evidence in young people is sobering. Lifestyle change alone has proven markedly less effective in adolescents than in adults, and many young patients require medication and still struggle to maintain control. That is exactly why early life prevention at the family and community level is essential. The most effective changes are shared across the whole household rather than placed on the child, everyday habits like family meals, water over sugary drinks, and being active together. But families need support to make those choices possible: nutritious school meals, daily physical activity, and safe, affordable access to healthy food in every neighbourhood. Since this disease falls hardest on the communities with the fewest resources, making the healthy option the easy option has to be something we value collectively."
