Receiver operating characteristics (ROC) curves of glycated hemoglobin (HbA1c) for diagnosis of prediabetes. (A) ROC curves of HbA1c for diagnosis of IFG (100• fasting plasma glucose <126 mg/dl, and HbA1c <6.5%). (B) ROC curves of HbA1c for diagnosis of IGT (140• 2-hr glucose <200 mg/dl, fasting plasma glucose <100 mg/dl, and HbA1c <6.5%). (C) ROC curves of HbA1c for diagnosis of IFG and/or IGT (fasting plasma glucose •100 mg/dl or 2-hr glucose •140mg/dl) in participants (fasting plasma glucose <126 mg/dl, 2-hr glucose <200 mg/dl and HbA1c <6.5%). *Area under the ROC curve (standard error). (†) p value for comparison of area under the curve (AUC) between groups. Women were compared with men, whereas Mexican American and non-Hispanic black with non-Hispanic White, and 60+years and 40–59 years with 20–30 years. ♦HbA1c 5.7%.