Glucose and Insulin responses in offspring of Nigerian Type 2 diabetics

Abstract

Type 2 diabetes mellitus has a strong genetic basis as evidenced by a concordance rate ranging between 60 and 90% in monozygotic twins. Glucose and insulin response s to an oral glucose load were measured in 52 offspring of Nigerian Type2 diabetics and 50 control subjects selected to achieve a similar distribution of age and gender. All subjects studied were glucose tolerant. In comparison with control subjects, offspring of Type2 diabetics had a significantly higher mean (SD) (I) fasting plasma glucose level [69.2 (13.0) mg/dl vs. 62.2 (7.6) mg/dl; P=0.0012] (ii) fasting plasma insulin level [26.6 (15.4) uIU/mi vs. 14.8 (6.8) uIU/ml; P<0.0001] (iii) 2 hours post glucose load plasma insulin level [59.8 (33.9) uIU/ml vs. 40. 9 (24.2) uIU/ml; P=0.0028]. The mean (SD) 2-hour post glucose load plasma glucose level did not differ significantly between both groups >f subjects [92.8 (23.8) mg/d l vs. 85.5 (21.3) mg/dl; P=0.11]. Further multiple regressional analysis showed that the differences in fasting plasma insulin a n d 2-hour post glucose load insulin observed were only accounted for by the presence of a parental history of diabetes and were n o t influence d significantly by BMI, waist and hip circumferences. This study shows that offspring of Nigerian Type2 diabetics have hyperinsulinaemia, despite being glucose tolerant and this supports the insulin-resistance hypothesis for Type2 DM. This implies that they are at a greater risk for developing diabetes mellitus and are therefore an important group for the primary prevention of Type2 DM.