Background: Healthy diet, such as greater adherence to Mediterranean diet (aMED), has been associated with a lower risk of gestational diabetes mellitus (GDM). However, foods characterizing aMED, such as fish and vegetables, are high in certain persistent organic pollutants (POPs) that are known to increase GDM risk. As such, it is critical to examine the joint associations of healthy dietary patterns and POPs exposure with GDM risk.
Methods: The study is based on a prospective multi-racial pregnant cohort in the U.S., the NICHD Fetal Growth Study (N=2,802). aMED in peri-conception/early pregnancy was derived using validated food frequency questionnaire. In total, 76 POPs of different classes were measured using blood samples collected at 8-13 gestational weeks. Pregnant individuals were categorized into four mixed groups based on the median values of aMED and POP concentrations. Binary logistic regression models were utilized to evaluate the joint associations of aMED and POPs with GDM.
Results: aMED and POPs exposure are jointly associated with GDM risk, with the lowest risk among women of high aMED score and low POP levels. For instance, the risk of developing GDM was ~80% lower among women with a high aMED score and low Polychlorinated Biphenyls (PCBs) levels as compared to those with a lower aMED score and high PCB levels [OR (95% CI): 0.18 (0.04, 0.86) (p-interaction=0.041)]. Further, high POP levels appeared to diminish the beneficial role of aMED on lowering GDM risk: women with a higher aMED score and high PCBs did not have a reduced GDM risk compared to those with a higher aMED score and low PCBs.
Conclusions: This study is one of the first to examine the association of healthy diet in early pregnancy with GDM while considering POP levels, and results suggest that future endeavours for promoting a healthy diet for the prevention of GDM may consider optimizing environmental contaminants such as POPs simultaneously.
G. Yu: None. W. Pang: None. J. Yang: None. C. Zhang: None.
