Risk factors for impaired glucose tolerance in obese children and adolescents

AIM: To investigate which obese children have an increased risk for impaired glucose tolerance (IGT), a risk factor for later diabetes. METHODS: We studied 169 European untreated obese children and adolescents with normal glucose tolerance at baseline. Waist circumference, fasting glucose, lipids, blood pressure, pubertal stage, 2 h glucose in oral glucose tolerance test (oGTT), and HbA1c were determined at baseline and 1 year later. RESULTS: One year after baseline, 19 (11.2%) children demonstrated IGT, 4 (2.4%) children had impaired fasting glucose, no (0%) child suffered from diabetes, and 146 (86%) children still showed normal glucose tolerance. At baseline, the children with IGT and with normal glucose tolerance in a one-year follow-up did not differ significantly in respect of any analyzed parameter, apart from pubertal stage. The children developing IGT entered puberty significantly more frequently (37% vs 3%, P < 0.001). One year after baseline, the children with IGT demonstrated significantly increased waist circumference, blood pressure values, insulin and triglyceride concentrations, and insulin resistance index HOMA. The children remaining in the normal glucose tolerance status 1 year after baseline did not demonstrate any significant changes. CONCLUSION: During the study period of 1 year, more than 10% of the obese children with normal glucose tolerance converted to IGT. Repeated screening with oGTT seems meaningful in obese children entering puberty or demonstrating increased insulin resistance, waist circumference, blood pressure, or triglyceride concentrations.