The aim of this study was to identify dietary predictors of plasma dioxin-like activity in women from the Danish National Birth Cohort. Associations between exposure and birth weight and infant development at 6 months were also explored. Diet was assessed in mid-pregnancy by a food-frequency questionnaire. One hundred nulliparous 25-35-year-old women of normal pre-pregnancy body-mass-index were chosen according to their intake of fatty fish, as fatty fish is a potential route of exposure. Intake of other foods of animal origin was also explored. Dioxin-like activity was measured in plasma using the Dioxin-Responsive Chemically Activated LUciferase eXpression (DR-CALUX) and quantified in toxic equivalents (CALUX-TEQs). Information on infant attainment of specific milestones was obtained by maternal report in a standardized interview. The sample mean was 46 pg CALUX-TEQ/g lipid. Plasma dioxin-like activity increased by 10.7 pg CALUX-TEQ/g lipid (95% CI: 1.8; 19.7) for the highest compared to the lowest tertile of total dietary fat intake but decreased by -9.8 pg CALUX-TEQ/g lipid (95% CI: -19.4; -0.2) for fatty fish intake. The inverse association for fatty fish was explained by lower intake of high-fat food groups such as red meat, fats and oils, which were also predictors of dioxin-like activity. Plasma dioxin-like activity was not associated with birth weight, but an inverse correlation was observed with total developmental score (Spearman r=-0.23, p=0.046). Our study indicates that dietary patterns associated with high fat intake may lead to increased plasma dioxin-like activity and in utero exposure might be related to early infant development.
Funding: Financial support for this study was obtained from the Nordic Academy for Advanced Study, the Nordic Working Group on Fishery Research, and the EU Integrated Projects NewGeneris (FOOD-CT-2005-016320) and EARNEST (FOOD-CT-2005-007036). The EU Integrated projects NewGeneris ( http://www.newgeneris.org ) and EARNEST ( http://www.metabolic-programming.org ) receive financial support from the Commission of the European Communities, under the FP 6 priority 5: food quality and safety.The Danish National Birth Cohort has been financed by the March of Dimes Birth Defects Foundation, Danish Heart Association, Danish Medical Research Council, and Sygekassernes Helsefond, Danish National Research Foundation, Danish Pharmaceutical Association, Ministry of Health, National Board of Health, and Statens Serum Institut.