Dietary trans fatty acids (TFAs) are primarily industrially produced and remain abundant in processed food, particularly in low- and middle-income countries. Although TFAs are a cause of adverse cardiometabolic outcomes, little is known about exposure to TFAs in relation to brain development. We aimed to investigate the effect of maternal TFA concentration during pregnancy on offspring head growth in utero and during childhood. In a prospective population-based study in Rotterdam, the Netherlands, with 6900 mother-child dyads, maternal plasma TFA concentration was assessed using gas chromatography in mid-gestation. Offspring head circumference (HC) was measured in the second and third trimesters using ultrasonography; childhood brain morphology was assessed using magnetic resonance imaging at age 10 years. We performed regression analyses adjusting for sociodemographic and lifestyle confounders and instrumental variable (IV) analyses. Our IV analysis leveraged a national policy change that led to a substantial reduction in TFA and occurred mid-recruitment. After adjusting for covariates, maternal TFA concentration during pregnancy was inversely related to fetal HC in the third trimester (mean difference per 1% wt:wt increase: - 0.33, 95% CI - 0.51, - 0.15, cm) and to fetal HC growth from the second to the third trimester (- 0.04, 95% CI - 0.06, - 0.02, cm/week). Consistent findings were obtained with IV analyses, strengthening a causal interpretation. Association between prenatal TFA exposure and HC in the second trimester or global brain volume at age 10 years was inconclusive. Our findings are of important public health relevance as TFA levels in food remain high in many countries.
RZ is supported by China Scholarship Council grant
(201606100056); HM is supported by Stichting Volksbond Rotterdam, the Brain and Behavior Research Foundation NARSAD Young
Investigator Grant (27853), and the Dutch Research Council (NWO)
Aspasia Grant (015.016.056); TW is supported by the Netherlands
Organization for Health Research and Development ZonMw TOP
project (91211921); HT is supported by the Netherlands Organization for Health Research and Development ZonMw Vici Grant (016.
VICI.170.200). This study was also supported by the European Union's
Horizon 2020 research and innovation program (733206 LifeCycle).
Supercomputing resources were supported by the Netherlands Organization for Scientifc Research (Exacte Wetenschappen) and SURFsara
(Cartesius Computer Cluster, www.surfsara.nl).