[Serum level of chemerin and bone mineral density in patients with Graves disease]

To investigate relationships between serum chemerin and bone mineral density (BMD) in patients with newly diagnosed Graves disease (GD).
 Methods: A total of 120 newly diagnosed GD patients with a course more than 3 months were enrolled from the Department of Endocrinology between June 2013 and June 2015. Sixty age- and sex-matched healthy people served as a normal control. Serum levels of chemerin, β-crosslaps (β-CTX), and N-MID-osteocalcin (N-MID-OT) were measured by ELISA. Fat mass and BMD were evaluated by dual energy X-ray absorptiometry (DEXA).
 Results: Compared with the normal control, the fat mass, lean weight, fat mass index (FMI) and body mass index (BMI) in the GD group were decreased, and BMD in all skeletal sites was decreased. There was a positive correlation between them (all P<0.05). Serum level of chemerin was increased and it was positively correlated with β-CTX or N-MID-OT level and negatively correlated with fat mass, FMI or BMI in the GD group. There was a negative correlation between chemerin level and BMD in femoral neck, total hip, lumbar or right forearm distal 1/3 (rs=-0.352, -0.279, -0.379, -0.289, -0.394; P<0.05). After adjusting for age, fat mass or BMI, the correlation of chemerin with total hip or bone mineral density remained significant (rs=-0.273, -0.378; P<0.05). Multiple linear regression analysis revealed that chemerin or BMI was correlated with BMD (P<0.05).
 Conclusion: The decrease of bone mineral density in patients with GD is not only related to the direct or indirect effect of excessive thyroid hormones on systemic and osteoblastic cells, but it is also related to the negative regulation of bone metabolism due to the elevated chemerin level.