New research to be presented at the Annual Meeting of The European Association for the Study of Diabetes (EASD) in Milan, Italy (Sept 28 – Oct 2) estimates the number of people living with type 1 diabetes (T1D) worldwide will increase by 29% from 9.4 million in 2025 to 12.1 million in 2049. In addition, it is estimated that the number of new cases per year will increase by 14% across this same period. The development of these estimates, using the DIAMOND-T1D model, has been led by Professor Anders Green, Steno Diabetes Center Odense, Denmark.
The EASD Annual Meeting host nation of Italy, along with other high-income countries (HIC), will see large increases in the numbers of people living with T1D (prevalence) in 2049 compared with 2025. For example, the UK will see numbers increase by around one third (more than 100,000) from 313,725 to 420,551 under the model. The USA will see an increase of over half a million, going from 1,492,825 to 2,055,235. Italy's increase of 16% is predicted to be less steep, but will still see an estimated 239,145 people living with T1D in the country in 2049, compared to 205,499 estimated in 2025. Despite this increase in prevalence, the yearly increase in new cases (incidence) will remain similar in 2049 compared with 2025 in these and other HIC. The authors suggest that the reasons for the predicted high incidence and prevalence in 2049 in countries such as Australia, US, UK are likely to be a combination of genetics, environmental triggers and also high case detection rates (due to the good health care infrastructure here and in other HIC).
And while low-income countries (LIC) such as Tanzania will see the rate of new cases per year double (from 3,275 to 6,177 per year from 2025 to 2049), the absolute numbers of people living with T1D in Tanzania will still be relatively low compared to HIC (again doubling, but from a relatively low 19,101 to 39,673).
Epidemiological data on T1D are limited, and especially scarce in low- and middle-income countries (LMIC). Accurate estimates of T1D incidence, prevalence and mortality rates are crucial for forming local and national health policies and for implementing the World Health Organization's 'Global Diabetes Compact' initiative – which aims to reduce the risk of diabetes and ensure that all people who are diagnosed with diabetes have access to equitable, comprehensive, affordable and quality treatment and care
Unlike previous estimates, the DIAMOND-T1D model takes historical patterns of insulin availability into account and aims to provide global, regional and country-specific estimates of T1D incidence, prevalence and mortality from 1900 to 2050. The model uses available data on T1D incidence, and population age distribution and survival combined with assumptions concerning age-specific incidence rates and mortality in T1D and the year of introduction of insulin in each country. The model has been validated against population-based registry data from Denmark and Scotland. Within the near future, the model will be available as a user-friendly open-access web-based system enabling users to create alternative country-specific epidemiological scenarios for T1D by changing key input variables.
The current DIAMOND-T1D model estimates a rise in global T1D incident cases per year from 530,024 in 2025 to 605,058 by 2049 (a 14% increase). The number of people living with T1D are estimated to increase by 29% from 9.4 million to 12.1 million over this period. Although the majority of people with T1D live in high-income countries (HIC) and middle-income countries (MIC), the largest relative increase in the T1D prevalence is expected to occur in LIC as access to insulin, glucose monitoring and survival all improve in those countries.
The 0-19 years age group was estimated to account for 42% of the incident cases in 2025, ranging from 37% in HIC to 49% in LIC. The 0-19 years age group was estimated to account for 15% of global all-cause deaths in the T1D population in 2025, ranging from 4% of deaths at all ages in HIC to 34% in LIC. For all-cause deaths among people living with T1D, the model estimates an increase from 361,383 in 2025 to 537,621 in 2049.
The figures below illustrate country specific examples of T1D incidence rates (per 100,000 population) and prevalence proportions (per 1000) from selected countries, according to World Bank income levels. The examples include Australia, UK, USA, Germany, Italy, France, India, South Africa, United Republic of Tanzania, Mozambique, Japan and China. The DIAMOND-T1D model therefore the option to compare country and regional T1D estimates, which is of considerable epidemiological interest.
Click here for graphs and table
Overall, the authors conclude: "We estimate a rising global T1D burden, underscoring the need to continue to improve access to insulin and quality of care, particularly in low-resource settings. Our prevalence estimates are lower than existing estimates from other sources including the T1D Index and the Global Burden of Disease Study mainly because of more conservative assumptions about survival in persons with T1D, particularly in older ages and low-income and middle-income countries. In this context, the DIAMOND-T1D model offers a novel approach that allows changes in key assumptions on age-specific incidence rates and survival in T1D, enabling informed decision-making, and at the same time making the model gradually more precise when more T1D data becomes available."
