July 12, 2024
Rising Levels of Thyroid Cancer

Rising Levels of Thyroid Cancer Linked to PFAS Chemicals in Water and Consumer Goods

A recent study published in the journal eBioMedicine has found a concerning link between exposure to per- and polyfluoroalkyl substances (PFAS) and an increased risk of thyroid cancer in human populations. Thyroid cancer rates have been on the rise globally, with a significant increase in incidence and mortality rates over the past few decades.

In the United States alone, there has been an average yearly increase of 3.6% in thyroid cancer incidence between 1974 and 2013. Similar trends have been observed in countries such as China, Italy, and Turkey. Even more troubling is the fact that the incidence rates of differentiated thyroid cancers (follicular and papillary thyroid cancers) among 10 to 19-year-olds in the United States have increased by approximately 4.4% per year between 1998 and 2013.

Endocrine-disrupting chemicals (EDCs) have long been suspected to play a role in the rising levels of thyroid cancer. PFAS are a group of these EDCs that have been widely used in various industries and consumer products since the 1940s. These chemicals have highly stable structures, making them ubiquitous in our environment. They can be found in soil, water, air, as well as in common consumer products like non-stick cookware, stain-resistant fabric, and firefighting foam. PFAS can also be present in food products and drinking water.

The study focused on investigating whether exposure to PFAS could increase the risk of thyroid cancer. Researchers analyzed plasma samples collected from 88 adult thyroid cancer patients and compared them with samples from 88 healthy individuals who served as a control group. The samples were analyzed using liquid chromatography-high resolution mass spectrometry to detect eight types of PFAS.

The findings revealed a significant correlation between PFAS exposure and thyroid cancer risk. Specifically, there was a 56% increase in the rate of thyroid cancer diagnosis per doubling of linear PFOS (perfluorooctane sulfonate) intensity in the entire study population. However, no significant association was observed between the other seven PFAS and thyroid cancer diagnosis rate.

Further analysis focused on patients with papillary thyroid cancer, and a similar positive association was found between linear PFOS intensity and the rate of thyroid cancer diagnosis.

Subgroup analyses were conducted to investigate the impact of exposure timing on thyroid cancer diagnosis. Patients who were diagnosed at least one year after sample collection showed a significant increase in the rate of thyroid cancer incidence when exposed to specific PFAS, including linear PFOS, branched PFOS, perfluorononanoic acid, perfluoro-octyl-phosphonic acid, and linear perfluoro-hexane-sulfonic acid. However, for cases diagnosed within one year after sample collection, only linear PFOS showed a similar association.

The study also shed light on why PFAS are considered carcinogenic. These chemicals have the ability to induce epigenetic alterations, immunosuppression, oxidative stress, inflammation, and disruption of hormonal and metabolic pathways.

A concerning aspect of PFAS is their persistence in the environment, particularly in drinking water. The half-lives of PFOS and PFOA (perfluorooctanoic acid) in water are 41 and 92 years, respectively. This emphasizes the long-lasting impact of these chemicals on human health through contaminated drinking water, which significantly increases the risk of thyroid cancer.

Furthermore, PFOS and PFOA have elimination half-lives in humans ranging from 3 to 7 years, indicating that they can continue to disrupt signaling pathways and pose potential health risks over an extended period.

As this study mainly focused on a select group of PFAS, researchers emphasize the need for large-scale prospective studies to further investigate the impact of exposure to additional PFAS on thyroid cancer risk. These efforts will help us better understand and address the growing threat of thyroid cancer associated with PFAS exposure in order to protect public health.

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  1. Source: Coherent Market Insights, Public sources, Desk research
  2. We have leveraged AI tools to mine information and compile it