Dietary guidelines adherence and pregnancy exposure to 10 classes of priority chemicals: an observational study in the Environmental influences on Child Health Outcomes Cohort.

BACKGROUND

Diet is a source of environmental toxicants; however, chemical exposures are not considered in the United States Dietary Guidelines for Americans (DGA).

OBJECTIVES

We tested whether higher DGA adherence was associated with gestational chemical exposures.

METHODS

Pregnant participants in the Environmental influences on Child Health Outcomes Cohort completed a food frequency questionnaire or 24-h recall at a median of 21 wk of gestation, which we used to calculate the Healthy Eating Index (HEI)-2015 total and individual component scores to assess DGA adherence. In spot urine samples collected at a median of 22 wk of gestation, we measured 113 analytes representing 10 chemical classes, including insecticides, fungicides/herbicides, organophosphate esters (OPEs), halogenated phenols, benzophenones, bisphenols, parabens, antimicrobials, phthalates/alternatives, and polycyclic aromatic hydrocarbons (PAHs). Using Bayesian generalized linear mixed-effects regression, we estimated covariate-adjusted percentage differences (β; biomarkers with ≥70% detection) or detection risk ratios (biomarkers with 30%-69% detection) and 95% credible intervals (CrIs) in urinary chemical biomarker concentrations for each 10-point increase in HEI-2015 total score. We used quantile-based g-computation to identify the top HEI-2015 component contributors to associations.

RESULTS

Most participants (n = 1492) self-identified as non-Hispanic White (40%) or Black (36%), and 50% had incomes ≥$50,000. The median (25th, 75th percentile) HEI-2015 score was 61.9 points (53.6, 70.2; of 100). We detected 53 analytes, representing biomarkers of 45 chemical parent compounds, in >30% of participants. Higher HEI-2015 scores were associated with lower OPE, halogenated phenol, bisphenol, phthalate, and PAH biomarker concentrations, most notably monobenzyl phthalate (β: -13.5%; 95% CrI: -21.0%, -5.8%). However, higher HEI-2015 scores were also associated with higher insecticide, paraben, and benzophenone biomarker concentrations, most notably benzophenone-3 (β: 16.2%; 95% CrI: 5.9%, 26.8%). Lower added sugar and higher protein, vegetable, fruit, and whole-grain intake were consistent predictors of lower or higher chemical biomarker concentrations.

CONCLUSIONS

Greater DGA adherence may minimize exposure to some, but not all, toxicants.