Differences in physiological response to an oral glucose tolerance test in adult Maasai men and women

AIMS: Rural, agro-pastoralist Maasai in East Africa exhibit low prevalence of diabetes, yet little is known about their physiological response to glucose loads and whether sex has an impact on glucose metabolism, including incretin hormones. METHODS: We included 58 (29 men, 29 women) adult Maasai without diabetes living in rural Tanzania. Clinical background characteristics were measured, and they were exposed to an oral glucose tolerance test (OGTT) after an overnight fast. Plasma glucose, insulin/C-peptide, glucagon, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1) were analysed. RESULTS: with two individuals being overweight and 14 being underweight. Men had a higher mean fasting glucose concentration (5.2 vs. 4.9 mmol/L, p = 0.031), while women exhibited a higher OGTT-derived mean GLP-1 concentration at 2-h (8.5 vs. 5.1 pmol/L, p = 0.005). Total area-under-the-curve (tAUC) for GLP-1 was higher in women compared to men (1336 vs. 870 pmol x min, p = 0.011). Sex- and BMI-adjusted regression analyses for tAUC showed higher values of insulin, C-peptide and GLP-1 in women (p < 0.10). CONCLUSIONS: Sex differences were found in fasting glucose and OGTT-derived insulin/C-peptide and GLP-1 concentrations. Research using more sophisticated methodology is needed to further explain the glucose metabolism phenotype in Maasai people.