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Scientists link ‘forever chemical exposure’ to liver damage

Scientists have identified a link between exposure to “eternal chemicals” and liver damage, as well as a potential link to non-alcoholic fatty liver disease, in a study published Wednesday.

Exposure to such compounds – also known as per- and polyfluoroalkyl substances or PFAS – was associated with elevated levels of a liver enzyme called ALT, which serves as a biomarker for liver damage, the scientists concluded. in a Environmental Health Perspectives article.

The authors synthesized the results of over 100 peer-reviewed studies in humans and rodents, ultimately concluding that three of the most common types of PFAS detected in humans – PFOA, PFOS, and PFNA – are all related to high levels of ALT in humans. some blood.

“PFAS are ubiquitous, and we know that every adult in the United States has detectable levels of PFAS in their bodies,” said Leda Chatzi, professor of population science and public health at Keck School of Medicine. from the University of Southern California. statement.

“There is growing interest in the long-term health effects of PFAS exposure, and this study confirms that there is evidence that PFAS are associated with liver damage,” Chatzi added.

Known for their presence in jet fuel fire-fighting foam and industrial releases, PFAS are also key components in a variety of household products, such as non-stick pans, rainwear and cosmetics.

So far, scientists have determined a “plausible linkbetween PFAS and diagnosed hypercholesterolemia, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer and pregnancy-induced hypertension.

The Environmental Health Perspectives study, however, is the first to establish such a link between PFAS and liver damage.

These so-called eternal chemicals have earned this epithet because of their propensity to slowly break down and accumulate in the environment and in human tissues, including the liver, according to the authors.

In addition to establishing the link between PFAS exposure and liver damage, the authors also identified a possible link to non-alcoholic fatty liver disease.

The liver enzyme ALT is also elevated in humans with this disease – a condition in which excess fat accumulates in the liver – suggesting a potential link between PFAS and what the authors described as a “dramatic increase and unexplained” disease in recent years. .

Non-alcoholic fatty liver disease has become a serious public health threat affecting 25% of adults worldwide, while cases in the United States are expected to increase by about a third by 2030, according to the study.

Evidence from animal studies has shown that PFAS, which are endocrine disrupting compounds, could cause metabolic changes that lead to fatty liver disease, the authors noted.

Epidemiological studies, they continued, have demonstrated links between PFAS exposure and cholesterol, triglycerides and uric acid, all of which are biomarkers of fatty liver disease.

Acknowledging that human research linking PFAS to liver disease is still limited, the study’s lead author, Sarah Rock, pointed out that there is plenty of evidence from animal research that demonstrates the toxic nature of PFAS to the liver.

“A challenge for PFAS researchers is that humans are exposed to mixtures of hundreds, if not thousands, of these chemicals,” Rock, a doctoral student at the Keck School of Medicine, said in a statement. “Mixture analyzes are a potential tool to address this complexity in the future.”

Although some US manufacturers have stopped using PFOA and PFOS, researchers have warned that the risk of exposure remains, due to the long-lasting nature of these compounds.

“This research clearly shows that PFAS should be taken seriously as a human health issue because even after removal, they persist in the environment,” said PhD student Elizabeth Costello, also the study’s lead author. in a press release.

“We believe there is sufficient evidence to demonstrate the need to clean up sources of PFAS exposures and prevent future exposures,” Costello added.