Compared with the control subjects, the values of BMI, HbA1C, TC, TG, LDL-C, CRP, Fins, HOMA-IR and skin AF were significantly increased (P<0.05), whereas the levels of irisin and HDL-C were significantly lowered (P<0.05) in type 2 diabetic patients. Here, FNDC5 is linked to type 2 diabetes mellitus.