- Researchers report that people exposed to chemical compounds known as PFAS had a 56% increased risk of thyroid cancer.
- The endocrine-disrupting PFAS chemicals are used in a variety of consumer projects.
- Experts say exposure to environmental PFAS chemicals is common and difficult to avoid.
Nearly everyone in the United States is exposed to synthetic chemicals known as PFAS.
Now, a new
Per- and polyfluoroalkyl substances (PFAS) are found in a wide range of consumer products, including nonstick cookware, water-repellent clothing, stain-resistant fabrics, and other products that resist grease, water, and oil.
In use since the 1940s, PFAS are so-called “forever chemicals” because they don’t easily break down and are widely found in soil, water, and air.
In their study, researchers compared 88 people with thyroid cancer to an 88-member control group of people who were cancer-free.
The researchers reported that exposure to a certain type of PFAS, called perfluorooctanesulfonic acid (n-PFOS), raised the risk of thyroid cancer by 56%.
An analysis of a subgroup of 31 people with thyroid cancer found an association between the disease and several other PFAS chemicals, including branched perfluorooctanesulfonic acid, perfluorononanoic acid, perfluorooctylphosphonic acid, and linear perfluorohexanesulfonic acid.
Researchers looked at exposure to a total of eight PFAS chemicals among the participants in the study.
“With the substantial increase of thyroid cancer worldwide over recent decades, we wanted to dive into the potential environmental factors that could be the cause for this rise,” said Dr. Maaike van Gerwen, a study co-corresponding author and an assistant professor and director of research in the department of otolaryngology/head and neck surgery at Mount Sinai Hospital’s Icahn School of Medicine in New York, said in a press statement. “This led us to the finding that PFAS… may at least partially explain the rise of thyroid cancer and are an area we should continue to study further.”
“To our knowledge, this is the first human study to find an association between exposure to certain PFAS and risk of thyroid cancer diagnosis,” van Gerwen told Medical News Today. “Our study results provide further evidence for the PFAS Health crisis underlining the need to remove/reduce PFAS from potential exposure routes.”
Nicole Deziel, PhD, a Yale Cancer Center researcher and associate professor of epidemiology at the Yale School of Public Health in Connecticut who was not involved in the study, told Medical News Today that the study findings are important for two reasons.
“First, thyroid cancer has been a fast-growing malignancy and its causes are not well-known,” she explained. “Second, PFAS and other endocrine disrupting chemicals have been linked to a variety of health problems, but their links to cancer and particularly thyroid cancer are less well-known.”
Dr. Ammar Sukari, an oncologist and member of the Thoracic Oncology Multidisciplinary Team at the Barbara Ann Karmanos Cancer Institute in Detroit who was not involved in the study, told Medical News Today that the research findings are not surprising.
“PFAS are known to
PFAS are endocrine-disrupting chemicals, said van Gerwen, “which means that these chemicals have an impact on glands in the body that produce hormones, including the thyroid gland.”
“From previous studies, it is known that PFAS
Exposure to PFAS may alter the levels or actions of thyroid hormones, leading to thyroid dysfunction or disease, said Sukari.
“PFAS can accumulate in the thyroid gland and affect its structure and function,” he said. “Studies have shown that PFAS can induce oxidative stress, inflammation, cell death, and DNA damage in the thyroid tissue, which may increase the risk of thyroid cancer.”
PFAS also may modulate the
“Some studies have suggested that PFAS exposure may impair the immune surveillance of thyroid cancer cells, allowing them to escape detection and elimination by the immune system,” he said.
Lauren Petrick, PhD, a study co-corresponding author and an associate professor of environmental medicine and public health at Mount Sinai, said that the study findings underlie the need to reduce and ultimately eliminate PFAS exposure.
“Today, it’s nearly impossible to avoid PFAS in our daily activities,” she stated in a press release. “We hope these findings bring awareness of the severity of these forever chemicals. Everyone should discuss their PFAS exposure with their treating physician to determine their risk and get screened if appropriate. In addition, we need continued industry changes to eliminate PFAS altogether.”
Toby Astill, PhD, the director of environmental and food safety in chromatography and mass spectrometry at the chemical testing lab Thermo Fisher Scientific who was not involved in the study, told Medical News Today that PFAS “have been used for decades in firefighting foams, food packaging, and consumer products, and because these compounds don’t break down, they stay in our environment forever. Their widespread use has led to the prevalence of PFAS that has made it harder to avoid throughout our everyday lives.”
“Fortunately, our understanding of PFAS and its associated health risks is improving,” said Astill. “My hope is that more of these studies continue to be implemented with wider scopes to contextualize the impact of PFAS. We especially need to track how PFAS compounds transport themselves in our ecosystems so we can then best limit their harmful effects down the line.”
Deziel said there are some ways to reduce exposure to PFAS.
“If you live in an area that has experienced contamination of drinking water, filters that have activated carbon or that use reverse osmosis can be effective,” she said. “One can also reduce or limit use of other sources such as nonstick cookware, grease-resistant food packaging like microwave popcorn bags and fast food wrappers, and reducing use of products like clothing that have stain-resistant treatments.”
Van Gerwen said her study group is also looking at hundreds of other chemicals and metabolites to see if any others are associated with thyroid cancer.
“We are also interested in further exploring the impact of PFAS exposure on thyroid cancer and thyroid cancer aggressiveness in population with high exposure to PFAS, for instance the U.S. military,” she said.
