Why Are Type 1 Diabetes Rates Rising?

Researchers predict that 2.7 million more people will be living with type 1 diabetes worldwide by 2049. But that does not mean 2.7 million additional people will be newly diagnosed.

By 2049, more than 12 million people worldwide could be living with type 1 diabetes—up from approximately 9.4 million in 2025.

That is an increase of 2.7 million people, or nearly 30 percent.

So, what is going on? Are more people developing type 1 diabetes? Is something in our environment triggering more autoimmune disease? Is obesity involved? Or are the numbers rising because we have gotten better at diagnosing T1D and keeping people alive?

The honest answer is probably a combination of several things. But there is also an important detail getting lost in some of the scarier headlines about this research.

What the new projection actually says

The new estimates were developed using the DIAMOND-T1D model, led by Professor Anders Green at the Steno Diabetes Center in Denmark.

Researchers estimate that approximately 9.4 million people worldwide were living with type 1 diabetes in 2025. By 2049, they predict that number will reach 12.1 million.

In the United States alone, the model predicts an increase from approximately 1.49 million people living with T1D today to just over 2 million by 2049.

But this does not mean researchers expect 2.7 million additional people to be newly diagnosed.

It means 2.7 million more people will be living with type 1 diabetes at that point in time.

The number of new diagnoses each year is expected to rise, too—but by approximately 14 percent. Researchers project an increase from roughly 530,000 new cases per year in 2025 to approximately 605,000 per year in 2049.

In other words, more people are developing T1D, but the much larger 29-percent increase refers to prevalence: the total number of people living with it.

That number is also affected by population growth, improved diagnosis, access to insulin, and the fact that people with type 1 diabetes are surviving and living longer.

More people living longer is good news

Part of the projected increase is actually good news.

In countries with reliable access to insulin, glucose monitoring, diabetes technology, and medical care, people with type 1 diabetes are living much longer than they did in previous generations.

In lower-income countries, many people still die because they cannot consistently access insulin or receive a correct diagnosis. Improvements in care could dramatically increase the number of people who survive and continue living with T1D.

The model predicts that some of the largest percentage increases will occur in lower-income countries for this reason.

For example, the number of people living with type 1 diabetes in Tanzania could more than double by 2049. That does not necessarily mean Tanzania will suddenly experience a massive increase in autoimmune disease.

Part of that increase could mean more people are correctly diagnosed, receive insulin, and survive.

A growing type 1 diabetes population is not automatically proof of a mysterious explosion in new cases. Some of that growth reflects meaningful progress.

New cases are still increasing

At the same time, we cannot ignore the other part of the story.

The number of people newly developing T1D each year is projected to rise globally. Researchers have also documented increasing rates of new diagnoses in many parts of the world for decades.

The frustrating answer to “Why?” is that we still do not completely know.

Type 1 diabetes develops when the immune system mistakenly attacks the insulin-producing beta cells in the pancreas. Genetics can make someone more susceptible, but genetic risk alone cannot explain such a significant change over only a few decades. Our genes do not change that quickly.

Researchers are therefore looking closely at environmental factors that may interact with genetic risk and help begin or accelerate the autoimmune attack.

Possible suspects include:

• Viral infections
• Changes in the gut microbiome
• Early-life nutrition
• Vitamin D levels
• Pollution
• Chemical exposures
• Other features of modern life

However, a possible suspect is not the same thing as a proven cause.

There is no single food, virus, chemical, parenting decision, or lifestyle habit that researchers can point to and say, “That is why this person developed type 1 diabetes.”

Is obesity causing more type 1 diabetes?

Some coverage of this research has dragged obesity into the headline, so let’s clear that up.

Type 1 diabetes is not caused by eating too much sugar. It is not caused by being lazy. It is not simply the result of gaining weight.

There is a theory known as the “accelerator hypothesis.” It suggests that insulin resistance may place additional stress on beta cells and potentially speed up the appearance of T1D in someone whose autoimmune attack is already underway.

Insulin resistance can be influenced by many things, including puberty, growth, genetics, illness, medications, hormones, and higher body weight.

That is very different from saying body weight causes type 1 diabetes.

Research examining the relationship between body size and T1D risk has also produced mixed results. There may be a connection for certain groups of children, but it would be only one potential piece of a much larger autoimmune puzzle.

Most importantly, this new projection did not investigate what is causing the increase. It is a modeling study estimating how many people may develop, live with, and die from type 1 diabetes under a set of assumptions.

It does not prove that obesity—or any other single factor—is responsible.

Type 1 diabetes is not just a childhood disease

Better recognition of adult-onset type 1 diabetes may also be affecting the numbers.

T1D was once commonly called “juvenile diabetes,” and that outdated idea is still causing harm.

Type 1 diabetes can develop at any age. Adults are frequently misdiagnosed with type 2 diabetes simply because they are adults—or because they live in a larger body.

As healthcare providers become more aware of adult-onset T1D and make better use of autoantibody and C-peptide testing, some people who would previously have been counted as having type 2 diabetes may finally receive the correct diagnosis.

Better detection increases the official numbers, but it also helps people receive appropriate treatment sooner.

These numbers are estimates—not destiny

It is important to remember that these figures come from a model.

Researchers combined the available data on type 1 diabetes incidence with information about population age, survival, mortality, and the historical availability of insulin in each country.

The model has been compared with registry data from Denmark and Scotland, but reliable information remains especially limited in many low- and middle-income countries.

The findings are being presented at the 2026 annual meeting of the European Association for the Study of Diabetes. These are projections—not a literal head count of every person with T1D on Earth.

That does not make the findings meaningless. It means they should be understood as informed estimates that can change as better information becomes available.

Why the projected increase matters

Whether the eventual number is exactly 12.1 million or somewhat higher or lower, the message is still significant.

Millions more people will need:

• Insulin
• Glucose monitoring
• Trained healthcare providers
• Diabetes education
• Emergency supplies
• Mental-health support
• Affordable long-term care

We cannot celebrate better diabetes technology if much of the world still cannot access basic insulin.

We cannot continue treating adult-onset type 1 diabetes like a rare exception.

We also cannot prepare for millions more people with T1D without addressing insulin prices, supply chains, healthcare infrastructure, and investment in prevention and cure research.

The future burden of type 1 diabetes will depend on more than how many people develop it. It will also depend on whether they are diagnosed before experiencing diabetic ketoacidosis, whether they can obtain insulin every day for the rest of their lives, and whether they have the tools and support needed to live well.

The bottom line

The number of people living with type 1 diabetes is clearly expected to rise, and the number of new diagnoses is expected to increase, too.

But the prediction of 2.7 million additional people living with T1D is not the same as 2.7 million new diagnoses.

That increase reflects a complicated combination of new cases, population growth, improved diagnosis, better access to insulin, and people with T1D living longer.

We still need much better research to understand why more people are developing the autoimmune disease in the first place.

And no—the answer is not simply that people are getting fatter.

Sources

• European Association for the Study of Diabetes. “Estimates Predict 2.7 Million Extra People Living With Type 1 Diabetes Globally by 2049.” August 28, 2026.
• Ogrotis I, Kountouri A, Korakas E, et al. “Changes in the Global Epidemiology of Type 1 Diabetes in an Evolving Landscape of Environmental Factors: Causes, Challenges, and Opportunities.” Medicina. 2023;59(4):668.