Scientists Discover a Hidden Type of Type 1 Diabetes—And It's More Common Than We Thought

For decades, doctors have understood Type 1 diabetes as a straightforward autoimmune disease: the body's immune system mistakenly attacks the cells that produce insulin, the hormone responsible for regulating blood sugar. But a groundbreaking study published in The Lancet in September 2025 is challenging that assumption—and it could reshape how we understand and treat this condition affecting an estimated 9.5 million people worldwide.

A Surprising Discovery in Africa

Researchers studied more than 1,000 children and young adults in Sub-Saharan African countries—Cameroon, Uganda, and South Africa—who had Type 1 diabetes. What they found was striking: about two-thirds of these young people had insulin deficiency (meaning their bodies couldn't produce enough insulin), but their condition wasn't caused by the autoantibodies that typically trigger Type 1 diabetes. In other words, their bodies weren't attacking their insulin-producing cells in the traditional way. Yet they still needed insulin to survive.

"This is not the end, but rather the beginning of work that lies ahead," said Dana Dabelea, PhD, director of the Lifecourse Epidemiology of Adiposity & Diabetes (LEAD) Center at the Colorado School of Public Health, who contributed to the research.

This New Subtype Isn't Just in Africa

Here's where it gets even more interesting for American readers: this atypical form of Type 1 diabetes isn't confined to Sub-Saharan Africa. When researchers examined data from the SEARCH for Diabetes in Youth study—a national, multi-center study that has tracked about 20,000 young people with diabetes over a quarter-century—they discovered that approximately 15% of those with Black ancestry also had this apparently non-autoimmune form of Type 1 diabetes.

The finding raises important questions about why the proportion differs so dramatically between regions. In Sub-Saharan Africa, about two-thirds of young people with Type 1 diabetes have this atypical form. In the United States, it's only about 15% of Black Americans. "What does that mean and why?" Dabelea asked.

Why the Differences? Multiple Theories Emerge

Scientists are exploring several explanations. One possibility is that the typical autoimmune form of Type 1 diabetes is more aggressive in Africa, and people with that form may experience higher mortality rates compared to those with the atypical form. Another theory involves genetics and environment working together differently across regions.

"What's possible is that the genetic predisposition to Type 1 diabetes is different between countries, even among populations that are ancestrally the same," Dabelea explained. "The interactions with viruses and things that trigger autoimmunity may also be different."

There's also a humbling possibility: researchers may simply not have discovered all the autoantibodies responsible for the autoimmune form in African populations yet. "Maybe we have not measured the antibodies in the African population that are responsible for the autoimmune form of the disease," Dabelea said.

Environmental Factors May Play a Bigger Role Than We Realize

Beyond genetics, environmental differences between regions could be significant. The TEDDY (The Environmental Determinants of Diabetes in the Young) study has identified important differences in environmental exposures that may trigger Type 1 diabetes, including maternal and infant diets, exposure to viruses, access to vaccines, and other factors—even among developed countries. These differences are likely even more pronounced between the United States and Sub-Saharan Africa.

What Comes Next?

While this discovery is exciting, Dabelea emphasizes that answers won't come quickly. Developing new treatments requires years of research, registries, and longitudinal studies to understand the causes and risk factors of this new diabetes form. However, history offers hope: previous long-term research commitments have yielded victories, including the widespread adoption of GLP-1 drugs for Type 2 diabetes and targeted treatments for MODY (maturity onset diabetes of the young).

"The more we know about the mechanisms leading to various subtypes of this disease, the better we will be to develop novel drugs and identify the best therapeutic options," Dabelea said. "Once we have them, access to those therapies for populations in our country and throughout the world is the next big thing."