RESUMO
BACKGROUND: Subjects with impaired glucose tolerance (IGT) are at risk for type 2 diabetes mellitus (T2DM) and cardiovascular disease. The predictors of IGT in obese youth are not well described. METHODS: We studied 115 obese Thai children who underwent an oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were calculated for assessment of ß-cell function. Hemoglobin A1c (HbA1c), lipid profile, and clinical parameters were also used to determine predictors of IGT. RESULTS: We found that three patients had T2DM and 30 subjects had IGT. IGT patients had significantly higher fasting glucose (FG), 1-h postload glucose, 2-h postload insulin, and lower whole-body insulin sensitivity indices than in normal glucose tolerance subjects whereas other indices were comparable. By ROC curve analyses, 1-h postload glucose was the best predictor of IGT, but FG or HbA1c represented a poor diagnostic tool for prediabetes screening. Subjects with 1-h OGTT glucose > 155 mg/dL had significantly lower high-density lipoprotein levels, lower insulin sensitivity, and more insulin resistance than those with 1-h postload glucose of ≤ 155 mg/dL. CONCLUSIONS: Abnormal glucose tolerance is highly prevalent in obese Thai youth. Several fasting indices and HbA1c fail to predict IGT. An 1-h OGTT glucose of > 155 mg/dL appears to be more associated with adverse insulin dynamics and metabolic profile than 2-h postload glucose.
