Associations between Pre-pregnancy Dietary Patterns and Gestational Diabetes Mellitus (GDM): a Retrospective Cohort Study

Abstract

BackgroundGestational diabetes mellitus (GDM) is a growing public health concern, with dietary factors playing a crucial role in its development. Understanding the impact of pre-pregnancy dietary habits on GDM risk is essential, as it could inform early nutritional interventions aimed at reducing the likelihood of GDM before pregnancy. However, the relationship between pre-pregnancy dietary patterns, food group consumption frequency, and GDM risk remains unclear. This study examines the association between pre-pregnancy dietary intake and GDM, using multiple dietary assessment approaches, including food group frequency analysis, the Dietary Inflammatory Index (DII), and principal component analysis (PCA)-derived dietary patterns. Methods A total of 633 women from a retrospective cohort study were included, with 95 developed GDM and 538 without. Dietary intake was assessed using a validated food frequency questionnaire (FFQ) administered pre-pregnancy. Chi-square tests and Wilcoxon rank-sum tests were used to compare baseline characteristics between groups. Multivariate binary logistic regression models were applied to examine the associations between food group consumption frequency, DII, PCA-derived dietary patterns, and GDM risk, adjusting for potential confounders such as age, pre-pregnancy BMI, pregnancy history, and socioeconomic factors. Results Food group frequency analysis revealed a significant inverse association between vegetable consumption and GDM risk. Compared to the lowest consumption group, participants with moderate vegetable intake had an 86% lower risk of GDM (OR = 0.140, 95% CI: 0.032–0.608, p = 0.009), while those with the highest vegetable intake had an 80% lower risk (OR = 0.196, 95% CI: 0.049–0.782, p = 0.021). Additionally, higher nut consumption was also associated with a lower GDM risk, with the highest intake group showing a 75% reduction in risk (OR = 0.255, 95% CI: 0.079–0.821, p = 0.022). PCA identified six major dietary patterns: "seafood-offal," "meat-based," "pickled-processed meat products," "vegetable-based," "mushroom-soy," and "cereal". Among these, the "cereal-based" pattern (characterized by higher wheat, grains, and rice intake) was associated with a significantly lower GDM risk (Q4 vs. Q1 OR = 0.44, 95% CI: 0.22–0.83, ptrend = 0.018). However, DII scores were not significantly associated with GDM risk in either unadjusted or adjusted models (p > 0.05). Conclusions These findings suggest that dietary habits, particularly adherence to frequent vegetable intake, nut consumption, and a cereal-based dietary pattern, may play a role in modulating GDM risk. However, DII scores and most individual food group intakes were not independently associated with GDM, highlighting the complexity of dietary influences on glucose metabolism. Future research should further investigate the protective role of vegetables, nuts, and whole grains, with an emphasis on the potential benefits of pre-pregnancy dietary interventions in reducing GDM risk. Keywords Gestational diabetes mellitus, pre-pregnancy diet, dietary patterns, principal component analysis, Dietary Inflammatory Index, nutritional epidemiology