The serum concentration of adiponectin in T2DM participants who developed MetS at the end of this study was 32.49 (31.97–34.03) ng/mL, significantly lower (p = 0.02) compared to the serum concentration of adiponectin before the onset of MetS [40.19 (39.27–41.32) ng/mL]. This evidence concerns the gene ADIPOQ and metabolic syndrome.