Uncovering Diabetes Diversity in Sub-Saharan African Youth
- FHS Communications
A study investigated the immune phenotype of diabetes in children and young adults across Cameroon, Uganda, and South Africa, challenging the assumption that most cases are autoimmune type 1 diabetes, as typically assumed in young patients.
Published in Lancet Diabetes and Endocrinology, the ‘Young-Onset Diabetes in sub-Saharan Africa (YODA) study’ enrolled 894 Black African individuals under the age of 30 who had been clinically diagnosed with type 1 diabetes. The main aim of the study was to determine how many participants had classical autoimmune type 1 diabetes, which has an earlier onset (childhood or adolescence) when compared to the more prevalent type 2 diabetes, which usually develops later in life. Type 1 diabetes is treated with exogenous insulin due to the severe insulin deficiency caused by the destruction of the insulin-secreting β-cells within the islets of Langerhans of the pancreas.
Autoantibody-positive vs autoantibody-negative
Tests revealed that 65.1% were autoantibody-negative, suggesting that most have a non-autoimmune form of diabetes. “The presence of different diabetes types means that a one-size-fits-all approach to treatment may not work, and the clinicians need to consider alternative diabetes subtypes when diagnosing and planning treatment for the children and young adults of African ancestry,” explains Dr Dhriti Sengupta, Researcher at the Sydney Brenner Institute for Molecular Bioscience (SBIMB).
All the type 1 diabetics in the study were receiving insulin therapy. Furthermore, Fellow Wits research and co-author, Professor Nigel Crowther, says that those who were autoantibody-negative had higher levels of C-peptide, a good measure of insulin secretory capacity. It is therefore feasible that these subjects may require lower insulin doses than those who were autoantibody positive.
Individuals were assessed using the Genetic Risk Score (GRS)—a numerical score reflecting the genetic contribution to the disease process. The analysis showed that autoantibody-positive individuals had a higher median GRS than autoantibody-negative individuals. “This suggests that those with the non-autoimmune form of type 1 diabetes have a lower genetic susceptibility for the disease,” says Professor Crowther.
Race dynamics
When comparing their data to that from the SEARCH for Diabetes in Youth study, in the United States, the non-autoimmune subtype of the disease was also observed in African Americans, but not white type 1 diabetic subjects diagnosed below the age of 20. A much lower prevalence (15.1%) was observed in the latter when compared to that in Africa (55.1%). Sengupta says this highlights that ethnic and environmental factors may play a significant role and that these findings “question the long-held assumption that insulin-dependent diabetes in young people is predominantly autoimmune”. She also suggested that this study demonstrates that “treatments based on studies in White populations may not always apply, underscoring the need for tailored approaches”.
Malnutrition
Malnutrition-associated diabetes has been well-documented in Africa and other populations. Although the YODA study did not find a link to malnutrition among its participants, other studies have linked poverty as a common risk factor for delayed development and diabetes endemic among young African individuals.
Improving diabetes care
The YODA study shows that not all young people in sub-Saharan Africa who are diagnosed with type 1 diabetes have the same form of the disease. Primary health providers should consider alternative diabetes subtypes when diagnosing young and older African patients. “Thus, it is possible that older patients who are lean and insulin-deficient may also have this form of non-autoimmune type 1 diabetes but have been misdiagnosed with type 2 diabetes,” says Crowther. Making subtype classification before treatment is crucial. Regular monitoring is important, as early intervention improves long-term outcomes. Notably, tracking diabetes subtypes through registries can inform future public health strategies.
Dr Sengupta stresses that proper screening is needed to spot those with type 1 diabetes, as if left undiagnosed, it can be fatal. She explains that this needs to be backed by better education and policy-focused research to “improve early diagnosis, access to care, and overall management of this distinct form of diabetes.”