Exposure to a whole soup of toxic forever chemicals can disrupt biological processes in children and young adults in a way that puts them at risk from diseases like cancer, diabetes and cardiovascular ailments.
That’s the “surprising” finding of a first-of-its-kind study from researchers at the University of Southern California’s Keck School of Medicine, published in Environmental Health Perspectives Wednesday, that has important implications for how per- and polyfluoroalkyl substances (PFAS) should be regulated.
“We are really only beginning to understand the range of effects that these chemicals have on human health,” study co-author and Keck School professor of population and public health sciences Leda Chatzi, M.D., Ph.D., said in a press release emailed to EcoWatch. “While current interventions have focused on phasing out the use of individual PFAS, such as PFOS and PFOA, this research shows why the focus should be on reducing exposure to all PFAS chemicals.”
PFAS are a class of thousands of chemicals that have been used in manufacturing since the 1940s. They are commonly found in firefighting foam and nonstick or waterproof products, to name a few. They are also widely dispersed in the environment and the human body, where some have a half-life as long as 25 years. It is estimated that 200 million U.S. residents use drinking water contaminated with levels of perfluorooctane sulfonic acid (PFOS) or perfluorooctanoic acid (PFOA) — two of the most common and dangerous PFAS — above the new health advisory set by the U.S. Environmental Protection Agency (EPA) in 2022. Furthermore, the Centers for Disease Control and Prevention has found that, since 1999, the PFAS PFOS, PFOA, perfluorohexane sulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) have shown up in the blood serum of nearly everyone 12 and older who the agency tested.
All of this is concerning because PFAS have been linked to a number of health problems including cancer, immunosuppression and reproductive or developmental issues. However, until now, it wasn’t clear how exposure to PFAS might disrupt metabolic pathways in order to cause these negative health effects, the study authors pointed out.
To try to fill in this gap, the research team looked at both PFAS exposure and changes to metabolic pathways in two groups of children and young adults. The study authors focused on young people because they are still developing and therefore more vulnerable to outside influences like PFAS and because it is during this time that the seeds for adult diseases are sown, the press release pointed out.
The two study groups were 312 overweight or obese adolescents from the Study of Latino Adolescents at Risk and 137 young adults from the Southern California Children’s Health Study. For each group, the researchers tested them for a variety of PFAS and also naturally occurring chemicals. Further, they developed a unique method to test how the PFAS were impacting the occurrence of the natural chemicals, which allowed them to assess both thyroid levels and the metabolism of amino acids and lipids.
What they found was that both groups had been widely exposed to a variety of PFAS, including PFOA, FOS, PFHxS and PFNA. What’s more, that exposure altered their metabolisms.
“Our findings were surprising and have broad implications for policy makers trying to mitigate risk,” study lead author and Keck assistant professor of population and public health sciences Jesse A. Goodrich, Ph.D., said in the press release. “We found that exposure to a combination of PFAS not only disrupted lipid and amino acid metabolism but also altered thyroid hormone function.”
The alteration of thyroid hormone was especially notable because this hormone plays an important part in human development during puberty. Any alterations to its function can influence the later development of cancer, diabetes, heart disease and other ailments.
“Together, our findings raise the possibility that increased risk of metabolic disorders associated with PFAS exposure are caused by alterations in thyroid hormones and mediated by changes in lipid metabolism,” the study authors wrote.
It is also notable that the effects in the study weren’t linked to any one PFAS but rather to a combination in the blood. Currently, the EPA’s renewed push to regulate PFAS has focused on PFOA and PFOS specifically, but the study indicates a more expansive approach is warranted.
“[O]ur findings lend support to the argument that PFAS should be regulated as a chemical class rather than being regulated on a chemical-by-chemical basis,” the study authors advised.
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