An international team of biologists and chemists has come up with a new framework to begin assessing the health effects of mixtures of chemicals that disrupt the endocrine system. Documented in the journal Science, this new combinatorial approach should make it possible to more rigorously link the effects of actual, daily exposure to endocrine-disrupting mixtures to health effects. Especially in children or more vulnerable individuals.
The study concerns a large cohort of mother-child pairs. The analysis confirms that exposure of pregnant women to combinations of endocrine-disrupting chemicals is associated with a risk of language delay in the child. This is the first-ever evidence of a link between certain combinations of chemicals and language delays. These findings underscore the need to take these combinations into account when conducting chemical risk assessment tests for these substances.
Better guidance on risk assessment strategies for EDs
Endocrine disruptors encompass a very broad class of chemical compounds, including Per- and polyfluoroalkyl substances (PFASs), phthalates, and phenols such as BPA. These disruptors are widespread in our environment and are found in a wide range of consumer products.
Many endocrine disruptors are known to interfere with hormone activity and the endocrine system; they are well documented to be associated with adverse health effects and disease in humans. These disruptors can also be transmitted from mother to child across the placenta and through breastfeeding, which can lead to neurodevelopmental disorders in newborns.
Multiple combinations: humans are rarely exposed to just one of these chemicals at a time; because these substances are widespread in the environment (air, water, and food), we are exposed to mixtures of disruptors on a daily basis. Today, however, risk assessment is performed for each of these chemicals individually. Little is known, therefore, about the adverse effects associated with endocrine-disrupting mixtures.
It is known, however, that the consequences of such exposures may be most harmful during prenatal exposure and during child development. While the long-term consequences are still unknown.
A 3-fold increase in the risk of language delay in highly exposed children
The team evaluated data on exposure to endocrine-disrupting mixtures in 1,874 mother-child pairs. This analysis showed that exposure to a mixture of these disruptive substances in early pregnancy is associated with language delay.
Experiments and studies on organoids and animal models already provide information on how these mixtures of compounds disrupt hormone pathways and interfere with gene expression.
Evaluation of children exposed to similar exposures in the study allowed the authors to identify areas of exposure of concern: 54% of children in the cohort had prenatal exposures above levels experimentally determined to be of concern, and these children had a 3.3-fold increase in the risk of language delay.
There is still a long way to go to determine the mixtures and levels of concern for humans, but the necessity for evaluating combinations of these compounds has been established.