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.
Objective and hypotheses: We aim to evaluate insulin dynamics and biochemical markers for predicting IGT in Thai obese youth.
Method: We studied 115 obese Thai children who underwent an oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were calculated for assessment of β-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, 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 fasting glucose or HbA1c represented a poor diagnostic tool for prediabetes screening. Subjects with 1 h OGTT glucose >155 mg/dl had significantly lower HDL levels, lower insulin sensitivity and more insulin resistance than those with 1-hr postload glucose of ≧155 mg/dl.
Conclusion: Abnormal glucose tolerance is highly prevalent in obese Thai youth. Several fasting indices and HbA1c fail to predict IGT. A 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.
01 - 03 Oct 2015
European Society for Paediatric Endocrinology