More On: chemicals in cookware
There is more and more evidence that regular exposure to 'forever' chemicals, which are made by people and used in many household products, is linked to a rise in the number of people getting cancer.
A new study that looked at the link between liver cancer and these chemicals in humans found that people with the highest levels of exposure have a 350% higher chance of getting liver cancer.
The term "forever" chemicals refers to the more than 4,700 types of perfluoroalkyl and polyfluoroalkyl substances, or PFAS, that are widely used in manufacturing. They are called "forever" chemicals because they break down very slowly and build up in soil, drinking water, and the body over time.
In the 1930s, PFAS were used for the first time to make nonstick cookware, like Teflon. They were soon used in all kinds of products and packaging, from building materials to cosmetics, because they are resistant to liquids and fire. The Centers for Disease Control and Prevention (CDC) says that PFAS are linked to a number of health problems.
Even though these chemicals are very useful, they have since been linked to cancer and other diseases in lab animals. Based on strong anecdotal evidence that perfluorooctanesulfonic acids (PFOS) and a common chemical called perfluorooctanoic acid (PFOA) were making people sick, the Environmental Protection Agency (EPA) told eight multinational companies with US offices to stop using these chemicals. Still, as their names suggest, PFOS and PFOA are still being found in products from other countries, in groundwater, and in people.
This study, which was published in JHEP Reports, is the first to show a clear link between any PFAS and nonviral hepatocellular carcinoma in humans, which is the most common type of liver cancer.
In a news release from the University of Southern California, Jesse Goodrich, a postdoctoral public health researcher at Keck School of Medicine, said, "This builds on the existing research and goes one step further." "Liver cancer is one of the worst outcomes of liver disease, and this is the first study in humans to show that PFAS are linked to this disease."
Scientists have had a hard time showing a link between PFAS and cancer in people.
“Part of the reason there has been few human studies is because you need the right samples,” added Keck School of Medicine professor Veronica Wendy Setiawan. “When you are looking at an environmental exposure, you need samples from well before a diagnosis because it takes time for cancer to develop.”
To make this leap, researchers were given access to the Multiethnic Cohort Study database, which entails a survey of cancer development in more than 200,000 residents of Hawaii as well as Los Angeles, Calif., conducted by the University of Hawaii.
Their search was narrowed to 100 survey participants — 50 of them with liver cancer and 50 without — whose available blood and tissue samples were sufficient for analysis. Researchers were looking for traces of “forever” chemicals present in the body before the group with cancer became ill.
They found several types of PFAS in the people who took part, with PFOS being the most common in the group with liver cancer. In fact, their research showed that people who were exposed to PFOS the most (in the top 10%) were 4.5 times more likely to get hepatocellular carcinoma than those who were exposed the least.
Because there is a clear link between PFAS and cancer in humans, it is important to learn more about how these chemicals affect the way our bodies work. USC scientists now think that high levels of PFOS in some subjects affected the liver's ability to break down glucose, bile acid, and branched-chain amino acids. This led to unhealthy levels of fat building up in the organ, which is called nonalcoholic fatty liver disease and is a high-risk factor for liver cancer.
Many scientists agree that it's not a coincidence that liver disease, cancer, and other illnesses are on the rise at the same time that "forever" chemicals are becoming more common and being used by more people.
“We believe our work is providing important insights into the long-term health effects that these chemicals have on human health, especially with respect to how they can damage normal liver function,” said study author Dr. Leda Chatzi. “This study fills an important gap in our understanding of the true consequences of exposure to these chemicals.”