Mediating effect of osteocalcin underlying the link between insulin-like growth factor-I and gestational diabetes mellitus.

Purpose: To investigate the associations of serum insulin like growth factor I (IGF-I) and Osteocalcin (OC) concentrations with gestational diabetes mellitus (GDM) risk among Chinese women.

Methods: A case-control study was conducted in China, involving 125 GDM and 153 healthy pregnant women at 24-28 gestational weeks from 2019 to 2022. The study was approved by the Clinical Trial Ethics Committee of the Third Afliated Hospital of Zhengzhou University in January 04, 2020, and the study had been registered with the Chinese Clinical Trial Registry (ChiCTR2000028811). Maternal serum IGF-I and OC levels were measured in the second trimester. Logistic regression models and restricted cubic spline (RCS) were employed to calculate the association of IGF-I and OC levels with the risk of GDM, and and receiver operating characteristic (ROC) curves were generated to evaluate the predictive capacity of IGF-I and OC for GDM. Mediation analyses were used to investigate the mediation effect of OC on the association between IGF-I and the risk of GDM.

Results: Both serum IGF-I and undercarboxylated Osteocalcin (ucOC) concentration were positively associated with the risk of GDM. The relationship between serum IGF-I and the risk of GDM is not linear (P-value < 0.001, P-Nonlinear < 0.001). Mediation analyses suggested that 48.61% of the associations between IGF-I and GDM might be mediated by ucOC. The areas under the ROC curves for IGF-I and integrated model were 74.5% and 76.2%.

Conclusions: Serum IGF-I might provide a new dimension in the diagnosis of GDM for clinical application, and ucOC might serve as a mediator between IGF-I and GDM.