Research reveals two distinct biological patterns in type 2 diabetes among lean and overweight African populations

A new study highlights the importance of recognising different biological mechanisms behind type 2 diabetes, particularly among lean individuals in Africa, demanding more personalised treatment approaches.

For years, type 2 diabetes has been framed mainly as a disease driven by excess weight. That picture is broadly correct, but research led by Amsterdam UMC and the University of Ghana suggests it can also obscure a second pattern affecting many lean people, especially in Africa. In a paper published in Diabetologia, the team argues that the same diagnosis can reflect different biological problems in different patients.

The familiar form of type 2 diabetes is usually linked to insulin resistance, where the body’s cells do not respond properly to insulin. Health organisations such as the CDC and reviews on obesity and diabetes have long noted the close relationship between excess body fat, disturbed metabolism and rising blood sugar. But the new study adds a crucial complication: some people develop diabetes not because they resist insulin, but because they do not make enough of it.

That distinction may be particularly important in African populations. The researchers examined data from more than 3,300 adults with type 2 diabetes in Ghana, Nigeria and Kenya, as well as people of African background living in Europe. They found that lean patients were more likely to have signs of too little insulin production, while heavier patients more often showed the classic insulin-resistant pattern. Lean patients were also more likely to develop diabetic eye disease and stroke, whereas higher-weight patients more often had high blood pressure and greater cardiovascular risk. Kidney disease appeared at similar levels in both groups.

The findings also raise questions about how diabetes is treated. Across much of Africa, patients are commonly given the same standard medicines regardless of body size or likely disease mechanism. The study points to the possibility that some lean patients may need treatment aimed more directly at limited insulin production, while others may benefit most from therapies that improve insulin sensitivity. The authors stress that this is not yet a basis for changing practice, and that clinical trials will be needed before treatment can be matched to diabetes subtype.

There are wider implications beyond the continent. Earlier research cited in the summaries suggests people of African ancestry may face diabetes risk at lower body mass index levels than Europeans, meaning weight-based thresholds developed elsewhere may miss important warning signs. The broader message from the new work is that type 2 diabetes is not always one disease in the same form, and that future care may need to look beyond body weight to the biology driving each patient’s condition.