Diet, polycyclic aromatic hydrocarbons, and oxidative stress biomarkers in pregnancy: A Los Angeles pregnancy cohort.

Polycyclic aromatic hydrocarbon (PAH) exposure during pregnancy has been associated with increased oxidative stress. Few studies have evaluated the relationship between diet, urinary PAHs, and oxidative stress biomarkers among pregnant women. We enrolled a prospective cohort of pregnant women who gave birth at UCLA between 2016 and 2019. Dietary intake over the past month was evaluated by a food frequency questionnaire during mid-pregnancy, and three diet index scores were calculated: Healthy Eating Index (HEI) 2015, Alternate Mediterranean Diet (aMED), and Alternate Healthy Eating Index for Pregnancy (AHEI-P). Urine samples were collected up to three times during pregnancy and analyzed for PAH biomarkers, including 2-hydroxyfluorene + 3-hydroxyfluorene (FLUO2FLUO3), 1-hydroxyphenanthrene (PHEN1), 2-hydroxyphenanthrene (PHEN2), 3-hydroxyphenanthrene (PHEN3), 4-hydroxyphenanthrene (PHEN4), 2-hydroxynaphthalene (NAP2), and 1-hydroxypyrene (PYR1), and two oxidative stress biomarkers, malondialdehyde (MDA) and 8-hydroxyguanosine (8-OHdG). We employed multiple linear regression models to estimate effects of diet on measures of urinary PAHs and oxidative stress biomarkers. A better diet quality, as indicated by three diet indices, was associated with lower urinary PAH metabolites and lower concentrations of oxidative stress biomarkers. This pattern appeared to be consistent across all three sampling periods (9-17 weeks, 18-29 weeks, and 30 weeks-delivery). Healthier diets may lower PAH exposure and oxidative stress in pregnancy.