Mediterranean diet, low exposure to organic pollutants reduces gestational diabetes risk
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Key takeaways:
- Participants on a Mediterranean diet with low persistent organic pollutants exposure had lower risk for gestational diabetes.
- These associations were more severe in women with prepregnancy obesity/overweight.
Among pregnant women, having low persistent organic pollutant exposure enhanced the protective association of an alternate Mediterranean diet against gestational diabetes, according to results published in Diabetes Care.
“These combined associations were more pronounced in pregnant women who were overweight or obese before pregnancy,” Cuilin Zhang, MD, PhD, MPH, founding director of the Global Centre for Asian Women’s Health, professor of obstetrics and gynecology and principal investigator with the Bia-Echo Asia Centre for Reproductive Longevity and Equality at the Yong Loo Lin School of Medicine with the National University of Singapore, and colleagues wrote.
Adoption of healthy diet plans such as the alternate Mediterranean diet (aMED) is commonly recommended to prevent the development of gestational diabetes. Ironically, several major food components of aMED, including root and leaf vegetables and seafood, are sources of certain persistent organic pollutants, which have been shown to increase risk for cardiometabolic disorders including gestational diabetes, according to the researchers.
Considering the lack of research investigating dual exposure to dietary patterns and persistent organic pollutants on gestational diabetes risk, the researchers performed a prospective population-based cohort study with data from 1,572 pregnant women (mean age, 28 years; gestational weeks, 8-13; 30.6% Hispanic; 30% Black; 20.6% white; 18.8% Asian or Pacific Islander) recruited from the U.S. Fetal Growth Study who had both persistent organic pollutant and food frequency questionnaire data, from which an aMED score was derived.
Researchers calculated concentrations of 76 persistent organic pollutants — including organochlorine pesticides, polybrominated diphenyl ethers, polychlorinated biphenyls (PCBs) and PFAS — based on plasma collected at recruitment.
Using multivariable logistic regression models, researchers evaluated the risk for gestational diabetes associated with aMED score and exposure to persistent organic pollutants.
Overall, 61 of the women (3.88%) had gestational diabetes.
The researchers found that higher total persistent organic pollutant levels appeared to mitigate the potential benefits provided by aMED on gestation diabetes risk, such that the risk was lowest among women with high aMED scores and low persistent organic pollutant concentrations.
Specifically, researchers observed a lower risk for gestational diabetes among women with a high aMED score and low summed polybrominated diphenyl ethers (logOR = –0.62; 95% CI, –1.09 to –0.15) or PCBs (logOR = –0.76; 95% CI, –1.44 to –0.09) compared with women with a low aMED score and high concentrations of persistent organic pollutants, who formed the reference group.
For PCBs, this remained significant even after adjusting for total lipids (logOR = –0.74; 95% CI, –1.41 to –0.07).
Finally, Zhang and colleagues found that these associations were more profound for women with prepregnancy obesity or overweight.
The researchers noted several limitations to this study, including that there may have been unmeasured covariates. Also, they noted that the persistent organic pollutant plasma concentrations were lower in this cohort than in the general population, which may have underestimated the observed effect.
“We observed that higher persistent organic pollutants appeared to diminish the potentially beneficial role of aMED in gestational diabetes, with the lowest risk of gestational diabetes being observed among participants with both greater adherence to the Mediterranean diet and low persistent organic pollutant concentrations, especially PCBs,” Zhang and colleagues wrote.
Future research should confirm and expand upon these study results by including diverse populations, larger sample sizes and different diets, they added.