'Forever Chemicals' Linked to Thyroid Cancer, Study Says

Particular per- and polyfluoroalkyl compounds (PFAS) have been linked by researchers to a higher risk of thyroid cancer.

PFAS, commonly called "forever chemicals," are a sizable, intricate family of synthetic compounds capable of migrating into the soil, water, and air through toxic chemicals. These molecules don't break down quickly in the environment because of the tight connection between carbon and fluorine.

Since the 1940s, chemicals have been utilized in consumer goods worldwide, including nonstick cookware, clothing that repels water, materials that resist stains, and other items that withstand grease, water, and oil.

PFAS are found in our drinking water, home care products, food, and the human body. Pregnant women are also at risk, as PFAS has been found in breast milk and infant formulas. Studies have long researched how these synthetic chemicals impact human health and how the levels of exposure have health risks.

PFAS exposure has been deemed a health issue by several national and international organizations, including the European Parliament and the United States Environmental Protection Agency (EPA). Previous studies have found that PFAS may play a critical role in being linked to testicular cancer, cardiovascular disease, and liver damage.

This research, by scientists from Mount Sinai, backs up the activities required to control and eliminate these per- and polyfluoroalkyl substances from exposure pathways. Not much research has looked at the connection between PFAS exposure and thyroid cancer in human populations, even though PFAS exposure has been noted as a possible factor — and endocrine-disrupting chemical — in recent rises in thyroid cancer.

"PFAS are a group of chemicals that all have a carbon-fluorine bond, which is a very strong bond. Because of this strong bond. PFAS do not degrade easily in the environment or our bodies. This is why PFAS are known as 'forever chemicals,'" shared Maaike van Gerwen, the co-corresponding author exclusively with Healthnews.

Given the widespread use of PFAS in our society, van Gerwen says that the danger of thyroid cancer from exposure to PFAS is a global issue. Critical data from this study complement more extensive investigations that examine the impact of PFAS exposure on the thyroid gland and thyroid hormone function.

Because of their ubiquitous presence in our environment, almost the entire population is exposed daily. PFAS have been associated with negative health impacts, including liver damage, pregnancy-induced hypertension, decreased response to vaccines, and developmental effects, including decreased birth weight. PFAS have also been associated with the disruption of thyroid hormone production. Our study is the first to find an association with thyroid cancer diagnosis.

- van Gerwen

She adds that PFAS belongs to the group of endocrine disrupting chemicals, 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 impacts thyroid hormone production. There are some hypotheses on why PFAS may cause or promote cancer however the exact mechanism is still unknown.

"Our study found that with increasing levels of certain PFAS, risk of thyroid cancer diagnosis went up significantly," said van Gerwen.

Using BioMe, a medical record-linked biobank at Icahn Mount Sinai, the researchers looked for correlations between plasma PFAS levels and the diagnosis of thyroid cancer. They compared 88 non-cancer controls matched on sex, race/ethnicity, age, body mass index, smoking status, and the year of sample collection to 88 thyroid cancer patients with plasma samples taken at or before cancer diagnosis.

From untargeted metabolomics, the researchers determined the concentrations of eight PFAS in blood samples from BioMe participants.

They also utilized several statistical methods to evaluate the accuracy, the concentrations of each unique PFAS were compared between the subjects who acquired thyroid cancer and those who remained healthy. The findings demonstrated that thyroid cancer diagnostic risk was elevated by 56% due to exposure to perfluorooctanesulfonic acid.

To account for the lag between exposure to PFAS chemicals and thyroid disease development, the researchers repeated the study in 31 patients.

Strong associations between PFAS and thyroid cancer

According to co-corresponding author Lauren Petrick, the study's findings further support the PFAS health effects during human exposure and highlight the need to minimize and eventually eliminate PFAS exposure to this class of chemicals.

Petrick says: "Today, it's nearly impossible to avoid PFAS in our daily activities. 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."

How to help diminish the spread of 'forever chemicals'

PFAS belong to the group of endocrine-disrupting chemicals, 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 impacts thyroid hormone production. There are some hypotheses on why PFAS may cause or promote cancer however the exact mechanism is still unknown. Our study found that with increasing levels of certain PFAS, the risk of thyroid cancer diagnosis went up significantly.

In the early 2000s, major American chemical companies voluntarily agreed to eliminate the production of PFOA and PFOA-related chemicals, which was one of the first PFAS produced. This does not mean that the production of PFAS declined. On the contrary, multiple new PFAS chemicals have been developed and are still being manufactured to date.

However, PFAS remained largely unregulated by the US Environmental Protection Agency (EPA) until 2021 when the EPA published a strategic roadmap, including nationwide PFAS monitoring and setting limits for PFAS in drinking water.

In 2022, the EPA proposed to designate PFOS and PFOA, the two most widely used PFAS, as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as Superfund, increasing transparency around PFAS release and polluter accountability.

To help society reduce the use of "forever chemicals," van Gerwen concludes that these efforts to regulate PFAS highlight the urgent need to tackle the PFAS crisis and are needed to reduce the use and exposure.