Impairment of cardiovascular autonomic pattern in obese adolescents with Type 2 diabetes mellitus

The aim of this study was to assess the behaviour of insulin sensitivity and insulin resistance indexes in a group of obese adolescents with type 2 diabetes in comparison to obese adolescents without diabetes and normal controls, moreover to compare these parameters with the cardiac autonomic pattern. 7 T2DM obese (12.7+/-0.5 ys), 18 obese without T2DM and 10 non obese control adolescents age matched were studied. In all subjects we performed OGTT with insulin and glucose determination, 24 h ECG Holter, blood pressure monitoring, ecohocardiogram. Results: serum lipids were significantly higher in obese and T2DM. Insulin sensitivity was significantly reduced in T2DM and obese vs. controls; T2DM showed a more pronounced oral glucose insulin sensitivity (OGIS) reduction vs obese. Both obese and T2DM presented an higher insulin resistance. T2DM showed an impaired beta cell function, with insulin areas under the curve and disposition index significantly reduced in comparison to controls and obese who showed similar values. A progressive reduction of vagal indexes and an increase of sympathetic indexes were found in obese adolescents and were more pronounced in T2DM. These parameters were correlated with oral glucose insulin sensitivity and beta-cell function parameters in both obese and T2DM adolescents. T2DM showed a significant relative wall thickness increase suggesting a trend toward concentric remodelling. In conclusion, T2DM adolescents are characterised by a more marked insulin resistance reduced beta-cell function in comparison to non diabetic obese. These modifications may lead to an early impairment of the autonomic pattern