Classical type 1 diabetes may not be the most common diabetes subtype in sub-Saharan Africa
Milomei/Aramie
Some sub-Saharan Africans suffering from the autoimmune disease disease type 1 diabetes actually have a newly recognized, non-automated immune form. This may require new treatment strategies.
Every person with diabetes has difficulty producing or using the hormone insulin, which is necessary to maintain healthy blood sugar levels. However, the causes of these problems may vary. In type 1 diabetes, the problem stems from the false immune system that destroys insulin-producing beta cells in the pancreas and marks those cells for disappearance using “autoantibodies” in the tail.
However, Jean Claude Nyabu Katt and his colleagues at the University of Exeter in the UK have shown that two-thirds of young sub-Saharan Africans diagnosed and treated with type 1 diabetes have none of these autoantibodies, indicating that their immune systems are not involved in insulin deficiency. They also lack the genetic risk factors predicting type 1, suggesting that there is a completely new form of diabetes.
Studies have shown that autoantibodies are present in sub-Saharan African sub-lower populations with type 1 diabetes compared to people with high-income regions such as Europe. However, researchers don't know exactly why this occurs because there is little robust data on type 1 diabetes in Africa.
As such, Kat and his team conducted the first multicountry study of the condition in sub-Saharan Africa. They examined the presence of three diabetic autoantibodies and genes predicting the risk of type 1 diabetes in 894 Black Africans in Uganda, Cameroon and South Africa. This group included young men and women aged 15 years. All participants had been diagnosed with type 1 diabetes and were treated with insulin.
The researchers found that 35% of participants had autoantibodies, very low insulin levels and a higher risk of type 1 diabetes. However, the other 65% did not produce autoantibodies, with slightly higher insulin levels, and the median genetic risk score for this group was 18% lower. However, they were still insulin deficiency, and the risk of type 1 was higher than their diabetic-free peers. Furthermore, there were no type 2 or malnutrition-based diabetes features.
Sylvanaobisi of Stony Brook Medicine in New York shows that this study demonstrates a major type of diabetes in sub-Saharan Africa.
The team also compared newly collected African data with information from over 3,000 US participants from the search for diabetes in adolescent studies. Autoantibody negative type 1 diabetes was detected only in 15% of Black American participants and 9% of White American participants. However, only black Americans without autoantibodies had a lower genetic risk for type 1 diabetes, similar to those observed in the African group. This suggests that white people without autoantibodies still suffered from autoimmune diabetes. Why is this group lacking them, as autoantibodies in type 1 diabetes can disappear over time?
The fact that Black Africans and Black Americans have this new non-automated immunological diabetes subtype suggests that both genetic and environmental factors may contribute to it. It could be caused by an unknown gene that induces “beta cell vulnerability,” Obici says. Alternatively, subtypes could be triggered by chronic infection, malnutrition in childhood, environmental toxins damage beta cells, or the presence of still wavy autoantibodies.
Further research is important as this new diabetes subtype could require a different standard of care, says Dana Dabelea of the Colorado School of Public Health.
“At this point, insulin remains the mainstay in treatment for this new diabetic subtype due to insulin deficiency,” Katt says. But ultimately, it needs to be identified to best deal with the true causes of subtypes, says Daverea.
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