In accordance with our data, J. Zhang et al. showed that serum FGF19 levels were significantly lower in normal glucose tolerance (NGT) subjects than in isolated-impaired glucose tolerance (I-IGT) subjects and isolated-impaired fasting glucose (I-IFG) participants based on glucose effectiveness (GE) and hepatic glucose production (HGP) [24]. This evidence concerns the gene FGF19 and Impaired glucose tolerance.