Elevated 1-h post-load plasma glucose levels in subjects with normal glucose tolerance are associated with unfavorable inflammatory profile

Glucose tolerant subjects with 1-h post-load glucose ≥155 mg/dl (NGT-1 h-high) are at increased risk for type 2 diabetes (T2DM). Prospective studies showed that chronic subclinical inflammation is a predictor of T2DM. In this study, we aimed to evaluate the inflammatory profile in NGT-1 h-high subjects as compared with individuals with 1-h post-load glucose <155 mg/dl (NGT-1 h-low). To this end, an oral glucose tolerance tests (OGTT) were performed in 1,099 nondiabetic whites. Cardio-metabolic risk factors including high-sensitivity C-reactive protein (hsCRP), erythrocyte sedimentation rate (ESR), fibrinogen, and complement C3 (C3) were determined. Of the 1,099 subjects examined, 497 had NGT-1 h-low, 154 had NGT-1 h-high, 158 had isolated impaired fasting glucose (IFG), and 290 had impaired glucose tolerance (IGT). As compared with NGT-1 h-low, NGT-1 h-high and IGT subjects exhibited significantly higher hsCRP, ESR, fibrinogen, and C3 levels. Notably, hsCRP, ESR, and C3 were also significantly higher as compared with IFG individuals. In a logistic regression analysis adjusted for age and gender, NGT-1 h-high and IGT subjects had a 1.8-fold increased risk of having the highest value of the Inflammatory Score. These data suggest that a value of a 1-h OGTT glucose ≥155 mg/dl may be helpful to identify a subset of normal glucose tolerance individuals at risk for chronic subclinical inflammation, a predictor of T2DM, and cardiovascular diseases.