The incretin effect in type 2 diabetes in a Sub-Saharan African population

Aim: Type 2 diabetes is increasing in Sub-Saharan Africa, but the pathophysiology in this population is poorly investigated. In Western populations, the incretin effect is reduced in type 2 diabetes, leading to lowered insulin secretion. The aim of this study was to investigate the incretin effect in a group of Sub-Saharan Africans with type 2 diabetes.

Methods: Twenty adults diagnosed with type 2 diabetes, based on either an oral glucose tolerance test (n = 10) or on glycated hemoglobin A1c (n = 10), and 10 non-diabetic controls were included in an interventional study in Tanzania. We investigated the incretin effect as the difference between the plasma insulin area under the curve during an oral glucose tolerance test and that obtained during an intravenous glucose infusion. Differences between diabetes groups were analyzed by Kruskal-Wallis one-way analysis of variance.

Results: The incretin effect did not differ between groups (p = 0.45), and there was no difference in plasma concentrations of the incretin hormones during the OGTT.

Conclusion: A reduced incretin effect appears not to contribute to hyperglycemia in type 2 diabetes in this Tanzanian population. More research is needed to explain the diabetes phenotype often seen in Sub-Saharan Africa.

Trial registration: Clinicaltrials.gov: NCT03106480 , date of registration: 04/10/2017.