Plasma visfatin levels were significantly higher in obese subjects with type 2 diabetes than in other categories of glucose tolerance: Normoglycaemia (NG): 9.69±3.77 ng/ml, prediabetes: impaired fasting glucose/impaired glucose tolerance (IFG/IGT): 9.61± 2.72 ng/ml, and Diabetes Mellitus (DM): 13.48± 9.66ng/ml; global p = 0.018, NG vs DM p = 0.007; IFG/IGT vs DM p = 0.016. This evidence concerns the gene NAMPT and diabetes mellitus.