Background
This study examined whether folate and vitamin B12 imbalance is associated with gestational diabetes mellitus (GDM) and explored interactions between B vitamin imbalance and maternal risk factors for GDM.
Methods
A cross‐sectional study was performed in 406 Chinese pregnant women. Serum folate, vitamin B12, and blood glucose concentrations were measured at 24 to 28 weeks gestation during GDM screening. A diagnosis of GDM was made based on International Association of Diabetes and Pregnancy Study Groups criteria (fasting plasma glucose [FPG] ≥5.1 mM, 1‐hour plasma glucose ≥10.0 mM, or 2‐hour plasma glucose ≥8.5 mM). Binary logistic regression was used to obtain odds ratios (ORs) after controlling for different confounders.
Results
Higher folate levels were associated with higher glucose concentrations and a higher risk of GDM (OR 1.98; 95% confidence interval [CI] 1.00‐3.90), whereas higher vitamin B12 levels were associated with lower FPG and a lower risk of GDM (OR 0.30; 95% CI 0.15‐0.60). A higher folate: vitamin B12 ratio was associated with higher glucose and a higher risk of GDM (OR 3.08; 95% CI 1.63‐5.83). The presence of both a higher folate: vitamin B12 ratio and advanced age further increased the OR to 2.13 (95% CI 1.09‐4.15) with a significant additive interaction. Furthermore, a higher folate: vitamin B12 ratio and a higher prepregnancy body mass index (pp‐BMI) were synergistically associated with an increased risk of GDM (OR 3.03; 95% CI 1.40‐6.57).
Conclusions
An imbalance between folate and vitamin B12, represented by a higher folate: vitamin B12 ratio, was highly associated with GDM risk, and this association could be further modified by maternal age and pp‐BMI.