Maternal dioxin-dietary patterns, prenatal exposure to dioxins and dioxin-like compounds, and birth outcomes in a European Mother-Child Study (NewGeneris)

Abstract

Background Diet is the main source of exposure to dioxins and dioxin-like compounds for the general population. The diet of pregnant women may affect exposure of the foetus to environmental contaminants and influence foetal growth. Aim We investigated the association between maternal diet and biomarker assessed dioxin levels in maternal and cord blood with birth outcomes in a European prospective mother-child study (NewGeneris). Methods Plasma dioxin-like activity was estimated by the Dioxin-Responsive Chemically Activated LUciferase eXpression (DR-CALUX) bioassay in maternal (n=604) and cord (n=198) blood samples collected at delivery in Denmark, England, Greece, Norway and Spain. We used food frequency questionnaires to assess maternal diet and reduced rank regression to identify two dioxin-dietary patterns related to maternal and cord blood dioxin levels (in DR-CALUX TEQ pg/g lipid), respectively. The dioxin-dietary pattern scores described participants’ adherence to each of the two dietary patterns. Results The dioxin-dietary pattern score was positively correlated with dioxin (DR-CALUX) levels in cord blood (rho=0.35, p<0.001) and was characterised by high maternal consumption of red and white meat, low-fat dairy and fast-food and low consumption of fatty fish and high-fat cheese. Dioxin-dietary pattern score in the upper tertile was associated with a reduction of half week in gestational age (95%CI:-1.0 to 0.0) and a non-significant reduction of 73 grams in birth weight (95%CI:-237 to 90) compared to the lower tertile, after adjustment for confounders. Similar negative adjusted associations with birth outcomes were observed for the dioxin-dietary score that was linked to dioxin (DR-CALUX) levels in maternal blood. Conclusions Maternal diet contributes to the exposure of the foetus to dioxins and dioxin-like compounds. We provide evidence that a dioxin-rich diet may be related to reduced gestational age and birth weight, mediated by high prenatal exposure to dioxin and dioxin-like compounds.