[Gestational diabetes mellitus-mediated association between serum resistin levels and large for gestational age]

Objective: To investigate the relation of serum resistin levels among pregnant women with the occurrence of large for gestational age (LGA) and its mediation by gestational diabetes mellitus (GDM). Methods: Pregnant women with 15-20⁺⁶ gestational weeks were recruited and followed until pregnancy termination. After trend tests for resistin levels and GDM and LGA incidence, restricted cubic spline (RCS) models were used to fit the risk curves for resistin levels concerning GDM and LGA. Log-binomial regression models weighted by the Copy's method were then applied to examine the relationship between high resistin exposure and both GDM and LGA, yielding adjusted RR and 95%CI after controlling for covariates. Finally, a causal mediation model was used to quantify the proportion of the association between high resistin exposure and LGA mediated by GDM via four-way effect decomposition. Results: A total of 1 481 pregnant women were included, with 270 cases of GDM (18.2%) and 241 cases of LGA (16.3%). Compared with the Q₁ group, the Q₃ and Q₄ groups had significantly higher risks of GDM, with adjusted RRs (95%CI) of 2.04 (1.74-2.39) and 3.61 (3.05-4.25), respectively. Similarly, the Q₂, Q₃, and Q₄ groups exhibited increased risks of LGA, with adjusted RRs (95%CI) of 1.29 (1.10-1.51), 1.46 (1.25-1.71), and 2.35 (2.00-2.76), respectively.Using receiver operating characteristic curve, the high-resistance cutoff was identified as 10.36 ng/ml. Pregnant women exposed to high resistin levels had 2.80 times (RR=2.80, 95%CI: 2.10-3.73) higher risk of developing GDM and 1.64 times (RR=1.64, 95%CI: 1.23-2.18) higher risk of developing LGA. Mediation analysis showed that GDM explained approximately 47.8% of the association between high resistin and LGA (mediation proportion: 13.4%; interaction proportion: 46.1%). Conclusions: High maternal serum resistin levels in mid-pregnancy are associated with an elevated risk of LGA, with nearly half of this risk mediated through GDM-related pathways. Serum resistin may serve as a biomarker for screening and intervening in GDM and LGA.