They’re in your pans, your makeup and your clothes — and now, scientists say they may be quietly putting teens at risk.
So-called “forever chemicals” have already been linked to a long list of health problems, including several types of cancer, immune system damage and birth defects.
A new study raises fresh concerns, suggesting that exposure to per- and polyfluoroalkyl substances (PFAS) during adolescence may sharply increase the risk of developing a dangerous condition that often goes unnoticed until it has caused serious damage.
That finding is especially troubling given how widespread PFAS exposure has become.
These manmade chemicals, designed to repel oil, water and stains, can be found in thousands of everyday products. They are notorious for seeping into the environment, where they can linger for years, contaminating drinking water, soil, air and wildlife.
Eventually, PFAS enter our bodies, with more than 98% of the US population carrying detectable levels in their blood.
In the new study, researchers analyzed 284 adolescents and young adults from Southern California who had participated in two long-term studies conducted by the University of Southern California’s Keck School of Medicine.
They tested participants’ blood for PFAS levels and used MRI scans to measure fat buildup in their livers.
The team found that higher levels of two common PFAS — perfluorooctanoic acid (PFOA) and perfluoroheptanoic acid (PFHpA) — were linked to a significantly greater risk of developing metabolic dysfunction-associated steatotic liver disease, or MASLD.
Formerly known as fatty liver disease, MASLD occurs when excess fat accumulates in the liver. It’s often tied to metabolic problems such as obesity, type 2 diabetes, high blood pressure and high cholesterol.
But here’s the twist: PFAS in the blood was linked to a higher risk of liver disease in teenagers, but not in young adults.
“Adolescents are particularly more vulnerable to the health effects of PFAS as it is a critical period of development and growth,” Dr. Shiwen “Sherlock” Li, the study’s lead author, said in a press release.
In fact, teens with double the amount of PFOA in their blood were nearly three times more likely to have MASLD.
The danger was even greater for adolescents with a specific genetic variant, known as PNPLA3 GG, that affects how the liver stores fat. Among young adults, smoking further worsened PFAS-related liver damage.
“These findings suggest that PFAS exposures, genetics and lifestyle factors work together to influence who has greater risk of developing MASLD as a function of your life stage,” said Dr. Max Aung, an assistant professor of population and public health sciences.
The study builds on earlier USC research showing that obese adolescents undergoing bariatric surgery had more severe liver disease — including inflammation and scarring — when exposed to PFHpA.
“Taken together, the two studies show that PFAS exposures not only disrupt liver biology but also translate into real liver disease risk in youth,” said Dr. Lida Chatzi, a professor of population and public health sciences.
“Adolescence seems to be a critical window of susceptibility, suggesting PFAS exposure may matter most when the liver is still developing,” she added.
The findings come as MASLD are expected to rise in the coming years. About 10% of US children are currently affected, but that number jumps to nearly 40% among kids with obesity, according to the American Liver Foundation.
The disease often flies under the radar, with many patients showing no obvious symptoms until it has progressed to advanced stages.
Left untreated, MASLD can lead to serious — even deadly — complications, including heart disease, fibrosis, cirrhosis and liver cancer. It is already the second leading cause of liver transplants in the US and is expected to become the top cause within the next decade.
“MASLD can progress silently for years before causing serious health problems,” said Chatzi, who also directs the ShARP Center, which is funded by the National Institute of Environmental Health Sciences to address PFAS contamination and its health impacts.
“When liver fat starts accumulating in adolescence, it may set the stage for a lifetime of metabolic and liver health challenges,” she added.
One study found that people with MASLD live about 2.8 years less, on average, than those without the disease.
But there’s some good news. Lifestyle changes — including a healthier diet, more physical activity and weight loss — has been shown to slow or even reverse liver damage, especially when caught early.
The new research suggests that limiting adolescents’ contact with forever chemicals could also make a difference.
“If we reduce PFAS exposure early, we may help prevent liver disease later,” Chatzi said. “That’s a powerful public-health opportunity.”
