A Newly Discovered Diabetes Subtype in Young People in Sub-Saharan Africa

Recent studies suggest that some individuals in sub-Saharan Africa diagnosed with type 1 diabetes may actually have a newly identified, non-autoimmune variant, necessitating a reassessment of current treatment approaches.

Diabetes affects every individual’s ability to produce or utilize insulin, a hormone essential for regulating blood sugar levels. However, the underlying causes differ. In classic type 1 diabetes, an autoimmune reaction destroys insulin-secreting beta cells within the pancreas, aided by “autoantibodies.”

Research led by Jean Claude Nyabou Cut from the University of Exeter reveals that approximately two-thirds of young sub-Saharan Africans diagnosed with type 1 diabetes lack these autoantibodies. This indicates that their insulin shortage might not be immune-related. Additionally, these individuals exhibit a lower predisposition to type 1 diabetes, suggesting an entirely new diabetes variant.

Studies have indicated autoantibodies are less prevalent among sub-Saharan Africans compared to their counterparts in affluent regions such as Europe. The reasons behind this discrepancy remain unclear, primarily due to the scarcity of comprehensive data regarding type 1 diabetes in Africa.

To address this gap, Kat and his colleagues conducted the first multicountry investigation of the condition across sub-Saharan Africa. They assessed three diabetic autoantibodies and the associated genetic factors in 894 Black Africans from Uganda, Cameroon, and South Africa, all of whom were diagnosed with type 1 diabetes and receiving insulin treatment.

The findings revealed that 35% of participants possessed autoantibodies, low insulin levels, and an elevated risk of type 1 diabetes. Conversely, the remaining 65% exhibited no autoantibody production, slightly higher insulin levels, and a median genetic risk score that was 18% lower. Despite this, they still experience insulin deficiency and a higher risk of type 1 diabetes compared to non-diabetic individuals. Notably, features typical of type 2 or malnutrition-related diabetes were absent.

Researchers including Silvana Obici from Stony Brook Medicine in New York contend that the predominant form of diabetes in sub-Saharan Africa is fundamentally different from classic type 1 diabetes.

The research team additionally compared their findings with data from over 3,000 participants in the US from the Search for diabetes in youth study. Autoantibody-negative type 1 diabetes was identified in only 15% of Black American participants and 9% of White American participants. Intriguingly, among Black Americans without autoantibodies, the genetic risk for type 1 diabetes was similarly low as that observed in the African cohort. This indicates that among White individuals, autoantibody absence does not equate to a non-autoimmune form of diabetes.

The presence of this new non-autoimmune diabetes subtype among both Black Africans and Black Americans highlights the potential influence of both genetic and environmental factors. Some hypotheses suggest it could be linked to an unidentified gene that induces “beta cell vulnerability,” as noted by Soumya Adhikari from Texas Children’s Health. Other possibilities include chronic infections, childhood malnutrition, environmental toxins disrupting beta cells, or the existence of atypical autoantibodies.

This emerging diabetes subtype may necessitate tailored treatment protocols, emphasizing the need for further research, according to Dana Douberry at the Colorado School of Public Health.

“Currently, insulin remains the primary treatment for this new diabetes subtype due to insulin insufficiency,” Katt acknowledges. However, identifying the fundamental causes of these subtypes is critical for improved management, asserts Daverea.