SIRT1 and Osteopenia: Furthermore, SIRT1 levels in T2DM patients with osteoporosis (DMo) were substantially lower than in NGT patients with osteopenia or osteoporosis (NGTo) (27.50 ± 7.95 vs. 32.34 ± 8.18 μmol/L, P < 0.05).However, no significant difference in serum SIRT1 levels was found between NGT patients with osteopenia or osteoporosis (NGTo) and those with normal BMD (NGTn) (32.34 ± 8.18 vs. 32.90 ± 7.32 μmol/L, P > 0.05), as illustrated in Figure 1.