Projected Burden Demands Investment and Equity in Type 1 Diabetes Care

With data from 1985 to 2025 showing cases of type 1 diabetes on the rise globally, and that incidence of the chronic autoimmune disease is disproportionately higher among persons from lower-income countries, experts of a new study in Diabetes Research and Clinical Practice highlight the importance of new epidemiological studies for inroads to care.¹

The authors propose that the higher numbers could be due to an increase in incidence stemming from a population growth, aging, or a decrease in mortality, and they say that a greater understanding of this global disease burden is paramount to health care resource allocation, health care professional training, and advocacy.

Using 2022 data from the International Diabetes Federation (IDF) Atlas, they estimated 2025 numbers and projected totals for 2040 in type 1 diabetes prevalence, incidence, and mortality; the Atlas has a 25-year history of estimating cases of symptomatic type 1 diabetes in children aged 0 to 14 years.² Methodology from the T1D Index was incorporated into the atlas in 2022, and estimates for patients aged 15 to 19 years were recently added.^3,4 Childhood data were available from 89 studies or data sets from 83 countries and adult data were available from 30 studies or data sets from 21 countries.

“Incidence data from the COVID-19 pandemic years 2020-2022 were excluded from the incidence over time model,” the authors wrote, “as a number of studies have shown marked temporal variations in incidence during this period.”

The authors’ estimates show that by the end of 2025, there will be approximately 9.5 million (95% CI, 9.0-10.0) people with a median age of 36 years living with clinically diagnosed type 1 diabetes around the world. Most will be aged 20 to 59 years (68.4%; 6.5 million) or younger than 20 years (19.0%; 1.9 million). Adults 60 years and older will account for 11.6% (1.1 million). Overall, 22.6% with diagnosed type 1 diabetes live in low- and middle-income countries.

Also in 2025, the US is estimated to have the highest estimated total cases of type 1 diabetes, at 1.5 million, with India (987,000), China (626,000), Brazil (517,000), and the United Kingdom (341,000) rounding out the top 5. However, for patients younger than 20 years, India will have the most cases, at 307,000, followed by 198,000 in the US; 120,000 in China; 101,000 in Brazil; and 72,000 in Egypt. According to the IDF, the regions with the highest totals of people living with type 1 diabetes are in Europe, North American/the Caribbean, and the Middle East and North Africa.

In addition, newly diagnosed cases are thought to top 513,000 for 2025 on a global scale. Close to half (43.3%; 222,000) will be seen in individuals younger than 20 years, and of this group, 74% (164,000) will be in adolescents younger than 15 years. The mean and median ages of diagnosis will be 28 and 24 years, respectively.

Potential reasons behind the higher total cases of type 1 diabetes seen in this study include population growth, aging, a decrease in mortality, and a greater understanding of this global disease burden. | Image Credit: Dvarg

Deaths worldwide are estimated to top 174,000 (95% CI, 109,000-266,000), and 27.3% (30,000) will be because the disease was not diagnosed. Most of these cases will likely be seen in Africa (6000) and Southeast Asia (10,000), and persons who are 25 years or younger will account for 64.8% (46,000) of this patient subgroup.

Compared with the general population, there was a significant gap in remaining life expectancy between the countries with the shortest and longest life expectancy following a diagnosis in 2025 for someone who is 10 years old at the time: 66 years in Norway (the longest and vs 74 years in the general population) and 6 years in South Sudan (the shortest and vs 55 years in the general population). If, however, the mortality rates of the type 1 diabetes and general populations matched, there is potential for an additional 3.4 million individuals living with type 1 diabetes to be alive at the end of 2025; this includes 669,000 who will die from nondiagnosis.

By 2040, there could be 14.7 million (95% CI, 11.5-19.3) people with type 1 diabetes worldwide, with the largest relative increases expected to be seen in Africa (120%), the Middle East and North Africa (86%), Southeast Asia (71%), Western Pacific (58%), South and Central America (55%), Europe (37%), and North America and the Caribbean (34%).

Of their results, the authors note the totals they saw for patients younger than 20 years were especially concerning, especially because low- and low-to-middle-income countries were disproportionately represented. However, these estimates are limited because they do not include premature deaths from type 1 diabetes that went undiagnosed, with most of these deaths attributed to ketoacidosis, misdiagnosis, or lack of access to care.

“The impact of variable T1D incidence, demography, and mortality between different countries and world regions highlights the importance of country-specific data for enabling accurate estimates of current and future burden of T1D,” the authors concluded. “National and global efforts to monitor T1D incidence, prevalence and mortality are essential for understanding current and future T1D burden. This in turn is fundamental to informing current and future health care service delivery for people with T1D and optimizing the care of all those affected.”

References

1. Ogle, GD, Wang F, Haynes A, et al. Global type 1 diabetes prevalence, incidence, and mortality estimates 2025: results from the International Diabetes Federation Atlas, 11th Edition, and the T1D Index Version 3.0. Diabetes Res Clin Pract. 2025:225:112277. doi:10.1016/j.diabres.2025.112277

2. IDF Diabetes Atlas 1st edition. International Diabetes Federation. 2000. Accessed June 4, 2025. https://diabetesatlas.org/resources/previous-editions/

3. Gregory GA, Robinson TIG, Linklater SE, et al; International Diabetes Federation Diabetes Atlas Type 1 Diabetes in Adults Special Interest Group. Global incidence, prevalence, and mortality of type 1 diabetes in 2021 with projection to 2040: a modelling study. Lancet Diabetes Endocrinol. 2022;10(10):741-760. doi:10.1016/S2213-8587(22)00218-2

4. Type 1 Diabetes Index. Accessed June 4, 2025. https://www.t1dindex.org/