Aim: To estimate insulin sensitivity in Type 1 diabetic children and adolescents, and assess the relationship between insulin sensitivity and clinical markers of adiposity and parameters of the metabolic syndrome.
Methods: A total of 202 patients aged 8-18 years with Type 1 diabetes and disease duration 1.5-15 years participated. Insulin sensitivity was estimated by glucose uptake during an euglycaemic-hyperinsulinaemic clamp and was calculated as the average amount of glucose (M(lbm) = mg/kg(lbm)/min) required to maintain euglycaemia. Blood pressure, glycated haemoglobin (HbA(1c)) and lipid concentrations were measured.
Results: The M(lbm )value ranged from 4.14 to 25.25 mg/kg(lbm)/min (mean 9.81 +/- 3.34 mg/kg(lbm)/min). There was a significant relationship between M value and patients' age (r = -0.38, P < 0.0001). Insulin sensitivity decreased significantly with the onset of puberty; hence, it was significantly lower in pubertal and post-pubertal adolescents. Girls were significantly more insulin resistant than boys (9.01 +/- 0.32 vs. 10.43 +/- 0.29 mg/kg(lbm)/min, P = 0.005). Insulin sensitivity correlated with body mass index (r = -0.29, P < 0.001), waist circumference (r = -0.35, P < 0.001), triceps skin fold (r = -0.17, P = 0.018), subscapular skin fold (r = -0.23, P = 0.001) and body fat (r = -0.19, P = 0.006). There was a relationship between M(lbm) value, cholesterol (r = -0.18, P = 0.012), high-density lipoprotein cholesterol (r = 0.15, P = 0.035), low-density lipoprotein cholesterol (r = -0.22, P = 0.002), triglycerides (r = -0.32, P < 0.001) and systolic blood pressure (r = -0.15, P = 0.029). Insulin resistance was related to HbA(1c) (r = -0.18, P = 0.012). Additionally, there was a correlation between M(lbm) value and insulin dose.
Conclusions: Children and adolescents with Type 1 diabetes mellitus have a very wide range of insulin sensitivity, which is determined by sex, age, amount of adipose tissue and glycaemic control.