Correlation between HOMA-IR and Pregnancy Outcomes of GDM Patients Under Vitamin D Insufficiency or Deficiency.

Background: This study aimed to assess the effect of vitamin D insufficiency or deficiency in early pregnancy on the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) in women with gestational diabetes mellitus (GDM) and to determine the correlation between HOMA-IR and pregnancy outcomes.

Methods: General clinical data, HOMA-IR, β-Cell function index (HOMA-β), and pregnancy outcomes were retrospectively analyzed in 248 GDM patients with vitamin D insufficiency and 81 GDM patients with vitamin D deficiency from September 2019 through April 20, 2023. The correlation between vitamin D and HOMA-IR was analyzed using multiple linear regression.

Results: Vitamin D-deficient GDM patients had reduced insulin sensitivity (i.e. increased HOMA-IR). Using a median HOMA-IR of 2.78 as the threshold, the incidence of preterm birth events in the cohort above the threshold was 11.90% (20/168), which was statistically different from that of the cohort below the threshold (p = 0.013). Women with GDM who had a vitamin D deficiency and had a HOMA-IR greater than 2.78 had higher rates of preterm labor (23.40%, 11/47) and transport to the neonatal intensive care unit (NICU) (21.74%, 10/46) than patients with vitamin D insufficiency (both p < 0.05). Multiple linear regression analysis showed a negative correlation between 25(OH)D and HOMA-IR (β, 95% CI: -0.14 (-0.18 - -0.10), p < 0.001), and the adjusted model was significant (β, 95% CI: 3.82 (1.61 - 6.04), p < 0.001).

Conclusions: Vitamin D deficiency is associated with reduced insulin sensitivity in women with GDM. GDM women with higher HOMA-IR and vitamin D deficiency are at an increased risk of adverse pregnancy outcomes.