Overweight patients with type 2 diabetes showed apparent insulin resistance (HOMA-IR; overweight patients vs. normal-weight controls, P = 0.027), and higher plasma leptin concentrations (leptin; overweight patients vs. normal-weight patients, P = 0.025, overweight patients vs. normal-weight controls, P = 0.021). This evidence concerns the gene LEP and type 2 diabetes mellitus.