Insulinogenic indices among type 2 Diabetic Nigerians

Abnormal pancreatic beta cell function is known to occur in type 2 diabetes mellitus. However, direct measurement of pancreatic beta cell function is cumbersome and virtually out of reach of most laboratories in developing countries. Fortunately, insulinogenic indices may be used as surrogate measures of beta cell function. To study insulinogenic indices among type 2 diabetic Nigerians. A cross sectional study involving 40 type 2 diabetic patients and 36 ageand sex-matched control subjects was undertaken. Diabetic patients and control subjects underwent standard oral glucose tolerance tests (OGTT). Fasting and post OGTT plasma insulin levels were measured using an ELISA technique, while plasma glucose levels were determined by a glucose oxidase method. Insulinogenic indices were calculated at time 30, 60, 90 and 120 minutes of OGTT. Diabetic subjects and controls were statistically compared. At 30, 60 and 90 minutes of OGTT, type-2 diabetic patients had significantly much lower insulinogenic indices compared to control subjects (p < 0.001). At 120 minutes of OGTT, however, the difference between the two groups was not statistically significant. Only BMI showed a positive correlation with insulinogenic index at 30 minutes of OGTT (r = +0.607, p < 0.001). There was no significant correlation between insulinogenic indices and duration since diagnosis of diabetes mellitus. Type 2 diabetic patients exhibit lower insulinogenic indices suggesting poor pancreatic beta cell function. (Int J Diabetes Metab 13: 167-169, 2005)