New study warns of millions of undiagnosed and missing people with type 1 diabetes

The global type 1 diabetes (T1D) burden continues to increase rapidly driven by rising cases, ageing populations, improved diagnosis and falling death rates, according to the results of a new modeling study being presented at this year's Annual Meeting of The European Association for the Study of Diabetes (EASD), Vienna (15-19 Sept).

The study estimates that T1D will affect 9.5 million people globally in 2025 (up by 13% since 2021), and this number is predicted to rise to 14.7 million in 2040. However, due to lack of diagnosis and challenges in collecting sufficient data, the actual number of individuals living with T1D is likely much higher, researchers say.

In fact, they estimate that there are an additional 4.1 million 'missing people' who would have been alive in 2025 if they hadn't died prematurely from poor T1D care, including an estimated 669,000 who were not diagnosed. This is particularly true in India, where an estimated 159,000 people thought to have died from missed diagnoses.

Our first priority should be to limit the rise in the number of people who are dying prematurely due to lack of diagnosis or suboptimal diabetes care. The number of these 'missing people' is expected to reach a staggering 6.7 million by 2040, yet millions of these lives could be saved with existing treatments and technologies."

Dr. Fei Wang, consultant with Breakthrough T1D, a research and advocacy organization in New York, USA

Co-author Dr Stephanie Pearson from Breakthrough T1D added, "Around the world, marginalised communities face significant barriers to T1D care.Theyare less likely to access or afford insulin and other essential medicines and technologies, struggle with poor glucose management, and experience reduced quality of life and shorter life expectancy. These new regional and country specific estimates represent a crucial step forward, equipping governments, health planners, and researchers with the insights needed to identify the populations most affected and to ensure that high-quality, affordable care is available to everyone, everywhere, when they need it."

The new analysis used data from the T1D Index and the International Diabetes Federation Atlas to estimate the prevalence (number of people living with the condition), incidence (new cases), deaths, and life expectancy of children, adolescents, and adults in 202 countries from 2021 to 2025, with forecasts of prevalence to 2040.

The study predicts that 513,000 new cases of T1D will be diagnosed worldwide in 2025, of which 43% (222,000) will be people younger than 20 years old. Finland is projected to have the highest incidence of T1D in children aged 0-14 years in 2025 at around 64 cases per 100,000.

More than half of people with T1D (5.4 million) were living in just ten countries in 2025-the USA, India, China, Brazil, the UK, Germany, Russia, Canada, Saudi Arabia, and Turkey (see tables at end of release).

Globally, 174,000 people are projected to die from T1D in 2025. Of these, around one in five (30,000) will be due to lack of a diagnosis, most of which will be in India with an estimated 6,000 deaths.

Stark inequities in care and outcomes

The analysis reveals substantial global inequities in diabetes care and outcomes in 2025, with remaining life expectancy at age 10 for people with T1D eleven times higher in Norway (66 remaining years) than in South Sudan (6 remaining years). In high-income countries, remaining life expectancy at age 10 was highest in Norway, (66 remaining years) and Sweden (66 years), and lowest in Guyana (35 years), Seychelles (39 years), and Trinidad and Tobago (40 years).

The study predicts a substantial (55%) rise in the global T1D population by 2040, with the greatest increases expected in Africa (up 120% to 829,000) and the Middle East/North Africa (up 86% to 2.78 million). Across Europe, numbers are expected to rise 37% to around 3.9 million, with the greatest increase seen in Kazakhstan (up 111% to 25,000).

The substantial increases in T1D forecasts between 2025 and 2040 underscore the urgent need for action. As co-author Renza Scibilia from Breakthrough T1D explains, "Early diagnosis, access to insulin and diabetes supplies, and proper healthcare can bring enormous benefits, with the potential to save millions of lives in the coming decades by ensuring universal access to insulin and improving the rate of diagnosis in all countries."

The authors note some important limitations to their estimates, including that while the analysis uses the best available data, predictions are constrained by the lack of accurate data in most countries-highlighting the urgent need for increased surveillance and research. They also note that data on misdiagnosis and adult populations remain limited, and the analysis assumes constant age-specific incidence and mortality over time. Furthermore, incidence data from the COVID-19 period were excluded from part of the modelling to avoid bias. Future updates are expected to improve as new data become available and applied.