The serum insulin concentrations at fasting, 1 h, 2 h and 3 h after OGTT in women of vitamin D group (obesity) were significantly lower than that in control group (obesity) (P = 0.041, P = 0.022, P = 0.030, P = 0.043). This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.