FNDC5 and type 2 diabetes mellitus: Moreover, subgroup analysis indicated that in the T2DM group, serum irisin levels were remarkably lower in patients with OP (DMo) than in patients with normal BMD (DMn) subjects (9.98 ± 2.09 vs. 11.39 ± 1.57 ng/ml, P < 0.01), but no such distinction was found between NGT with OP (NGTo) and NGT with normal BMD (NGTn) subjects (11.31 ± 2.23 vs. 11.79 ± 2.01 ng/ml, P > 0.05), which is displayed in Figure 1.