One-year follow-up of untreated obese white children and adolescents with impaired glucose tolerance: high conversion rate to normal glucose tolerance.

AIMS: Impaired glucose tolerance (IGT) is regarded at risk factor for later diabetes. The aim of this study was to identify predictive factors for outcome of IGT in obese children and adolescents.
METHODS: We prospectively examined 79 obese white children and adolescents (mean age 13.1 +/- 2.1 years, 51% female, 76% pubertal) with IGT. Anthropometrics, 2-h glucose in oral glucose tolerance test (OGTT), fasting glucose, insulin, insulin resistance index homeostasis model assessment (HOMA), glycated haemoglobin (HbA(1c)), lipids, blood pressure, waist circumference and pubertal stage were determined at baseline and 1 year later.
RESULTS: At follow-up, 32% of the children continued to have IGT, 66% converted to normal glucose metabolism, one child had impaired fasting glucose and one child developed Type 2 diabetes mellitus (T2DM). Children with improvement of IGT had significantly lower weight, waist circumference, triglycerides, 2-h glucose during OGTT and HbA(1c) at baseline compared with children who continued to have IGT. In the children whose glucose tolerance became normal, weight fell, and serum insulin concentrations, HOMA, lipids and blood pressure improved. They were also more likely to enter the late or post-pubertal stage than children who continued to have IGT.
CONCLUSIONS: Predictive factors for the frequent normalization of IGT in obese children and adolescents were lower weight, HbA(1c) and 2-h glucose levels in OGTT at baseline, as well as a reduction of weight and entering late puberty stages during follow-up. Cardiovascular risk factors and HOMA improved along with the improvement of IGT, supporting an association between IGT, insulin resistance and features of the metabolic syndrome.