A new diabetes subtype identified in Sub-Saharan Africa and Black Americans, study finds

An international team of researchers has made a key discovery: many children and young adults in Sub-Saharan Africa diagnosed with type 1 diabetes (T1D) may have a different form of the disease - one not caused by the immune system, unlike classic T1D. This discovery could change how diabetes is diagnosed, treated and managed across the region, paving the way for more accurate care and better outcomes.

The research was published today in Lancet Diabetes and Endocrinology.

“This is the first study across several Sub-Saharan African countries to use the same lab tests and genetic tools to learn more about type 1 diabetes. We've done similar research in the U.S. with different groups, but what's exciting here is being able to compare results between Africa and the U.S.,” said the paper’s co-author Dana Dabelea, MD, PhD, Distinguished Professor and Associate Dean of Research at the Colorado School of Public Health on the University of Colorado Anschutz Medical Campus.

The researchers enrolled 894 participants with youth-onset diabetes from three African countries: Cameroon, Uganda and South Africa. They compared findings from this population with similar studies done in the U.S. in the same age range.

“It’s a really unique and important opportunity to explore the heterogeneity of T1D across countries and racial groups living in vastly different environments," adds Dabelea, who is also the director of the Lifecourse Epidemiology of Adiposity and Diabetes (LEAD) Center at CU Anschutz.

The researchers found that many young people in Sub-Saharan Africa diagnosed with T1D often don't have the usual markers in their blood (called islet autoantibodies) typically seen in people with T1D in other parts of the world. Specifically, 65% of participants with T1D in this region did not have islet autoantibodies.

Islet autoantibodies help distinguish T1D from other forms of diabetes, like type 2 or monogenic diabetes, which have different causes and treatments.

“This suggests that many young people in this region have a different form of T1D altogether and is not autoimmune in origin,” said Dabelea.

When the researchers compared this data to studies in the U.S., they found a smaller but significant proportion (15%) of Black participants diagnosed with T1D had a similar form of diabetes found in Sub-Saharan Africa - characterized by negative autoantibodies and a low T1D genetic risk score.

However, white Americans with T1D showed the typical autoimmune pattern, even if they didn’t have detectable autoantibodies, their genetics still pointed to autoimmune diabetes.

“The identification of this T1D diabetes subtype in Sub-Saharan African populations and among individuals of African ancestry in the U.S. suggests a potential ancestral or genetic link,” Dabelea notes. “These findings highlight the need to consider alternative etiologies in this group and a deeper understanding of the underlying mechanisms may provide important insights for future prevention and treatment strategies.”

About the University of Colorado Anschutz Medical Campus

The University of Colorado Anschutz Medical Campus is a world-class medical destination at the forefront of transformative science, medicine, education and patient care. The campus encompasses the University of Colorado health professional schools, more than 60 centers and institutes and two nationally ranked independent hospitals - UCHealth University of Colorado Hospital and Children's Hospital Colorado – which see more than two million adult and pediatric patient visits yearly. Innovative, interconnected and highly collaborative, the CU Anschutz Medical Campus delivers life-changing treatments, patient care and professional training and conducts world-renowned research fueled by $910 million in annual research funding, including $757 million in sponsored awards and $153 million in philanthropic gifts.