In 2003, the American Diabetes Association (ADA) established a new cutoff for impaired fasting glucose (IFG) by reducing it from 110 to 100 mg/dL. This change was challenged as to its appropriateness. A few studies have examined the impact of the ADA(2003) threshold of IFG on metabolic and cardiovascular risk factors.
We examined whether metabolic and cardiovascular risk factors, including inflammatory biomarkers, differ in subjects with the new ADA(2003) threshold of IFG (IGF100) as compared with subjects with the old ADA(1997) threshold of IFG (IFG110) in a cohort of 946 nondiabetic Italian Caucasians (fasting plasma glucose < 126 mg/dL).
As compared with normal fasting glucose (NFG), subjects with IFG100 and IFG110 had higher body mass index (BMI), waist circumference, total and low density lipoprotein (LDL) cholesterol, triglyceride, fasting and 2-h post-challenge plasma glucose, fasting insulin, systolic blood pressure, and lower levels of high density lipoprotein (HDL) and insulin-like growth factor I (IGF-I). In a logistic regression analysis with adjustment for age and gender, IFG110 was associated with higher risk of post-challenge glucose intolerance as compared with IFG100. As compared with IFG100, subjects with IFG110 have significantly lower levels of circulating IGF-I. As compared with NFG, IFG110, but not IFG100, showed a significant association with increased levels of inflammatory markers including white blood cell count (WBCC), and C-reactive protein (CRP). Both CRP and WBCC were correlated with 2-h plasma glucose but not with fasting plasma glucose (FPG).
The data show that IFG110 is associated with a worse metabolic and cardiovascular risk profile as compared with IFG100.