Impact of Prenatal Exposure to Endocrine Disruptors on Child IQ

Study Overview

Researchers from the Icahn School of Medicine at Mount Sinai, along with teams from Sweden and Finland, evaluated the effects of prenatal exposure to a combination of 26 suspected endocrine disruptors (EDCs) on the IQ scores of seven-year-old children. This study, published in Environment International, is notable for its focus on the cumulative impact of EDC mixtures on neurodevelopment, contrasting with earlier research that typically examined single EDCs.

Research Methodology

The research utilized data from the Swedish Environmental Longitudinal Mother and Child, Asthma and Allergy (SELMA) study, which analyzed blood and urine samples from 718 mothers during the first trimester of their pregnancies. The investigation specifically measured various substances, including phthalates, bisphenols, perfluoroalkyl substances (PFASs), organochlorines, and other transient pollutants. Seven years post-exposure, psychologists assessed the children’s IQ, employing Weighted Quantile Sum regression and repeated holdout validation to evaluate the impact of the EDC mixture and to identify specific chemicals of concern.

Findings on IQ Scores

The study revealed that children, particularly boys, whose mothers exhibited higher levels of the EDC mixture during pregnancy, had IQ scores that were, on average, two points lower. Bisphenol F (BPF), a substitute for the harmful bisphenol A (BPA), was identified as the most significant contributor to the decline in IQ, suggesting that BPF may pose similar risks regarding neurodevelopmental outcomes as BPA. Notably, when regression analysis was conducted without BPF, the IQ scores remained consistent, indicating that BPF alone does not account for the entire effect on cognitive ability.

Chemicals of Concern

The research highlighted other chemicals linked to lower IQ scores, primarily comprising short-lived pollutants. These included 3, 5, 6-trichloro-2-pyridinol (TCP), found in insecticides; monoethyl phthalate (MEP), present in personal care products; and perfluorooctanoic acid (PFOS), commonly used in non-stick cookware and food packaging.

Environmental Context and Health Implications

Given the prevalence of EDCs in the environment, food, consumer products, and building materials, prenatal exposure is nearly unavoidable. Even at low concentrations, EDCs can disrupt hormone balance, with previous studies indicating associations between substances like phthalates and BPA and neurodevelopmental challenges in children. While the precise biological mechanisms remain unclear, researchers suspect that interactions among multiple EDCs may lead to unforeseen hormonal changes. There is concern that even brief prenatal exposure to these disruptors may result in lasting health issues into adulthood. Consequently, minimizing prenatal exposure to EDCs is critical for protecting children’s health.

Study Limitations and Future Research

However, the study did not take into account the socioeconomic status of families when evaluating IQ scores, nor did it consider the effects of EDC exposure during later stages of pregnancy and childhood. Future research is essential to validate the negative impacts of BPF and other replacement chemicals, emphasizing the need for further investigations in this area.

References

Tanner, E. M., Hallerbäck, M. U., Wikström, S., Lindh, C., Kiviranta, H., Gennings, C., & Bornehag, C.-G. (2019, October 24). Early prenatal exposure to suspected endocrine disruptor mixtures is associated with lower IQ at age seven. Retrieved from https://www.sciencedirect.com/science/article/pii/S0160412019314011#f0010.

(n.d.). Chemicals in consumer products during early pregnancy related to lower IQ. Retrieved from https://www.eurekalert.org/pub_releases/2019-10/tmsh-cic102319.php.

Image by Raman Oza from Pixabay.