Total insulin output is low in type-2 diabetic Nigerians

Background: Plasma insulin levels among type 2 diabetic patients are modulated by racial and ethnic factors. In contrast to the plethora of reported studies on plasma insulin levels among type 2 diabetic patients in technically advanced regions of the world, there is paucity of such information in Africa in general. Objective: To study insulin output among type 2 diabetic Nigerians. Subjects and methods: Forty type-2 diabetic and 36 healthy subjects underwent a standard oral glucose tolerance test (OGTT). Fasting and post OGTT plasma insulin levels were measured using an ELISA technique. Integrated insulin responses were calculated using trapezoidal estimation to compute total insulin output. Student’s t test was used to compare means; the level of statistical significance in each case was taken as p < 0.05. Results: The age and sex distribution of diabetic patients and control subjects were similar (p >0.5). Average duration of diabetes was 5.6 ± 4.3 years (range 1 -20 years) Total insulin output was significantly lower among type 2 diabetic patients than in control subjects (360 ± 82.1 microunits per ml and 745.1 ± 109.0 micro-units per ml respectively P<0.00 1). Conclusion: Type-2 diabetic patients in this study exhibit hypoinsulinaemia; this could be the explanation for the pattern of diabetic complications among type 2 diabetic Nigerians observed in previous studies.