Insulin-like growth factor binding protein 1 predicts insulin sensitivity and insulin area-under-the-curve in obese, nondiabetic adolescents

Objective: To compare fasting insulin-like growth factor binding protein 1 (IGFBP-1) to other fasting indices as a surrogate marker of insulin sensitivity and resistance calculated from a 3-hour oral glucose tolerance test (oGTT). Methods: Fasting IGFBP-1 and oGTT were performed at 0 (n = 77), 52 (n = 54), and 100 (n = 38) weeks in a study investigating metformin treatment of obesity in adolescents. Insulin area-under-the-curve (IAUC) and the composite insulin sensitivity index (CISI) calculated from the oGTT were compared to fasting IGFBP-1, homeostasis model assessment-insulin resistance, and corrected insulin release at the glucose peak (CIR gp). Results: IGFBP-1 and the ratio of IGFBP-1 to fasting insulin were significantly correlated with indices based on timed sampling, including IAUC, CISI, and CIR gp. In addition, a significant effect of IGFBP-1, but not IGFBP-1 to insulin at time zero, was observed for IAUC and CISI. Conclusion: Our results indicate that fasting IGFBP-1 may be a useful marker of insulin sensitivity and secretion.