RÉSUMÉ
Objective: To examine the associations between plasma n-3 polyunsaturated fatty acids (PUFAs) in the second trimester and gestational diabetes mellitus (GDM) among Chinese pregnant women. Methods: Based on data from the Tongji-Shuangliu Birth Cohort enrolled from 2017 to 2019 in the Shuangliu Maternal and Child Health Hospital, it conducted a case-control study among 269 GDM cases who were diagnosed by 75 g oral glucose tolerance test, and 538 non-GDM controls matched at a 1∶2 ratio on maternal age and gestational weeks. The age range of the 807 women was 18-40 years. Fasting plasma n-3 PUFAs were determined by gas chromatography-mass spectrometry in the second trimester (24-28 weeks). Participants were categorized into quartiles (Q1-Q4) of plasma n-3 PUFAs based on distributions in the control group. Conditional logistic regression models were applied to estimate the associations between plasma n-3 PUFAs and GDM. Results: The median (interquartile) relative concentrations of plasma n-3 PUFA C22∶5n-3 was significantly lower in women with GDM 0.87 (0.72, 1.07) compared with women without GDM 0.94 (0.75, 1.19)(P=0.001). Plasma n-3 PUFA C22∶5n-3 was inversely associated with GDM, with an OR (95%CI) of 0.75 (0.62-0.90) for each SD increase of relative concentration. Compared with the Q1 group, the OR values and 95%CIs of Q2, Q3, and Q4 groups were 0.97 (0.62-1.51), 0.72 (0.45-1.15), and 0.54 (0.32-0.90), respectively (Ptrend<0.05). However, there were no significant associations of C18∶3n-3, C20∶5n-3, C22∶6n-3, and total n-3 PUFAs with GDM. Conclusion: Plasma n-3 PUFA C22∶5n-3 was inversely associated with GDM during the second trimester.