A study from Amsterdam UMC and the University of Ghana, published in Diabetologia, found that type 2 diabetes presents through two distinct pathways that vary according to a patient's body weight. The research found that whereas insulin resistance tends to drive type 2 diabetes in people with a higher body mass index, those at the lower end of the BMI spectrum are more likely to develop the condition due to inadequate insulin production by the pancreas.
Notwithstanding these divergent physiological pathways, both patient groups are currently prescribed identical pharmaceutical treatments. Historically, the condition has been linked primarily to excess body weight in public understanding.
Among higher-income nations, roughly nine in ten people diagnosed with type 2 diabetes also carry excess body weight. Conditions across the continent vary considerably. Research indicates that roughly 38% of African adults diagnosed with type 2 diabetes maintain a lean physique, falling within a normal or below-average weight range. Across certain rural regions, including parts of Ghana, the proportion reaches approximately six out of every ten.
Lead author Sabrina Esmail noted that approximately 10 million low-weight patients across the African continent fall outside the conventional diagnostic profile. Charles Agyemang, a lead researcher at Amsterdam UMC, noted that the findings point to a need for tailored therapies for this population of non-obese African patients, adding that across the continent both patient groups typically receive identical treatment protocols, drawn from international guidelines and centred on oral medications such as metformin or sulfonylureas. "Their condition therefore stems from insufficient insulin production rather than impaired insulin response," Agyemang said.
The medication targets insulin resistance in the body rather than compensating for reduced insulin output. Findings indicate that some individuals may have been administered inappropriate therapies, and the extent of the resulting outcomes had not previously been examined.
The study drew on records from over 3,300 Black adults living with type 2 diabetes across Ghana, Nigeria, Kenya and Europe. Felix Chilunga, the study's lead author, noted that the findings pointed to a higher likelihood of eye damage — referred to as retinopathy — and strokes among patients with lower body weight. Individuals carrying excess body weight tend to face elevated rates of hypertension and a heightened likelihood of developing heart-related conditions.
Rates of chronic kidney disease were comparable across both groups, and adipose tissue volume appears to account for many of the observed variations, pointing to distinct underlying pathological mechanisms. The contributing factors also vary: excess body weight tends to be associated with poor dietary and activity habits, while those on the lower end of the weight spectrum more frequently show histories of nutritional deficiency or low birth weight, either of which can interfere with normal pancreatic development.
Research indicates that type 2 diabetes presenting in non-obese individuals of African origin may have distinct biological and clinical characteristics compared with the condition observed in those carrying excess body weight. The issue has nonetheless been treated as though no differentiation applies, and vast numbers of people may be going without appropriate treatment as a result.
Chilunga called for targeted clinical trials to identify the most effective treatments for this population, noting that people of African descent living in Europe may also require distinct therapeutic approaches. Research drawing on UK Biobank records found that individuals of African ancestry face a comparable type 2 diabetes risk at a body mass index of 26 to that observed among European-ancestry populations at a BMI of 30.
Research conducted among immigrant populations in Europe indicates that individuals of sub-Saharan African descent face a higher prevalence of type 2 diabetes, with onset occurring roughly a decade earlier and glycaemic management proving more difficult compared with host-country populations, according to multiple studies. Agyemang noted that a substantial share of patients of African heritage living in Europe present with lower body mass index readings, yet receive care based on treatment protocols developed around an overweight patient profile, resulting in measurably poorer health outcomes. "There is no indication that the treatment disparity outlined here is confined to this particular region," Agyemang said.
