Insulin secretion and insulin sensitivity in Bangladeshi type 2 diabetic subjects

Background and Aims: The relative role of insulin deficiency and insulin resistance seem to vary in T2D patients depending on race, age, body weight and other factors. The present study was undertaken to measure insulin secretion and insulin sensitivity in middle aged, normal to overweight Bangladeshi T2D subjects who constitute major bulk of diabetic patients in the country. Materials and Methods: Twenty-five newly diagnosed T2D patients, 10 age- and BMI-matched IGT and 10 control subjects were studied. Insulin secretory capacity was evaluated by glucagon stimulated C-peptide value and insulin sensitivity was measured by short insulin tolerance test. Results: T2D patients showed substantially lower insulin secretory capacity compared to Controls and IGT subjects as evidenced by serum C-peptide levels in response to unit glucose both in basal [Fasting- C-peptide/glucose ratio, mean +/- SD, nmol/mmol: 0.13 +/- 0.03 in Control; 0.09 +/- 0.04 in T2D and 0.12 +/- 0.05 in IGT, M +/- SD; p < 0.006 for Control vs T2D and p < 0.05 for IGT vs T2D groups] and in glucagon stimulated [GSC-pep-glucose ratio: 0.26 +/- 0.09 in Control; 0.23 +/- 0.09 in IGT and 0.14 +/- 0.07 in T2D, p < 0.001 for Control vs T2D and p < 0.003 for IGT vs T2D] state. There was no fasting hyperinsulinemia in the diabetic subjects; however their insulin sensitivity was found to be significantly compromised compared to Controls [K-ITT in mmol/l/min: 0.097 (0.07-0.27) in Control vs 0.065 (0.02-0.12) in T2D subjects, median (range); p < 0.001]. Insulin sensitivity of IGT subjects did not differ significantly from Control subjects. Conclusions: The data suggest that deficient insulin secretory capacity and insulin resistance both are present in the majority of Bangladeshi type 2 diabetic subjects.