The association between dietary patterns before pregnancy and gestational diabetes mellitus: a matched case-control study in China.

Background and objectives: We aimed to explore the relationship between dietary patterns and gestational diabetes mellitus (GDM) during pre-pregnancy six months using principal component analysis (PCA) and the geometric framework for nutrition (GFN).

Methods and study design: We conducted a case-control study that included 210 GDM pregnant women and 210 controls. The dietary intake of all participants was assessed by a validated semi-quantitative food frequency questionnaire (FFQ). Major dietary patterns were extracted by PCA. A conditional logistic regression model was used to determine whether specific dietary patterns are associated with the risk of GDM. Meanwhile, the relationship between dietary patterns and GDM was visualized using GFN.

Results: Four major dietary patterns were identified: "protein-rich pattern," "plant-based pattern," "oil-pickles-desserts pattern," and "cereals-nuts pattern." After adjustment for confounders, the "plant-based pattern" was associated with decreased risk of GDM (Q4 vs. Q1: OR = 0.01, 95% CI: 0.00-0.08), whereas no significant association was found in other dietary patterns. Moreover, there was no dietary intake of ice cream cones and deep-fried dough sticks for the population, which would produce fewer patients with GDM. Deep-fried dough sticks had statistically significant differences in the case and control groups (p < 0.001), while ice cream cones had the opposite result.

Conclusions: The "plant-based pattern" may reduce the risk of GDM. Besides, although the "cereals-nuts pattern" had no association with GDM risk, avoiding the intake of deep-fried dough sticks could decrease GDM risk.