Glucose dysregulation in obese children: predictive, risk, and potential protective factors

The aim of our study was to determine the prevalence of impaired glucose tolerance (IGT) and type 2 diabetes (DM2) in obese children and adolescents of Greek origin and compare our data with pertinent literature findings in an attempt to uncover predictive, risk, and preventive factors.

A total of 117 obese children and adolescents 12.1+/-2.7 years old underwent a 2-hour oral glucose tolerance test (OGTT). Insulin resistance (IR) and beta-cell function were estimated using the homeostasis model assessment (HOMA)-IR and the insulinogenic index, respectively.

A total of 17 patients (14.5%) had IGT, and none had DM2. The overall prevalence rates of both IGT and DM2 in our subjects were lower than those reported in a recent multiethnic U.S. study. Nevertheless, the difference between our IGT data and those of the U.S. study was due mostly to the prepubertal subjects (9% vs. 25.4%), whereas no difference was observed in the pubertal population (18% vs. 21%). Fasting glucose, insulin, and HOMA-IR values were not predictive of IGT. The absolute value of insulin at 2 hours of the OGTT combined with the time-integrated glycemia (AUCG) can strongly predict IGT, whereas higher area under the curve for insulin (AUCI) values were found to be protective.

In ethnic groups less prone to diabetes development, IGT or DM2 in obese subjects is more likely to develop at puberty than at the prepubertal stage. It is advisable that physicians caring for obese adolescents perform an OGTT for early detection of IGT because HOMA-IR values, although higher in IGT subjects and indicative of IR, cannot predict IGT.