PFAS chemicals linked to thyroid cancer, human data suggests

By Shannon Kelleher

Exposure to some per- and polyfluoroalkyl substances (PFAS) may increase thyroid cancer risk, according to a study published Tuesday.

The analysis, which compared blood samples from 88 people who developed thyroid cancer with samples from people who did not, is the first to document an association between PFAS and thyroid cancer, which had been previously hypothesized. Past research has linked these endocrine-disrupting chemicals to thyroid disease, a condition in which the gland produces too many or too few hormones. The new research adds to a growing list of health problems linked to PFAS, including kidney cancer, testicular cancer, ulcerative colitis, high cholesterol, and hypertension during pregnancy.

The study, which looked at eight different types of so-called “forever chemicals,” found that doubly high levels of perfluorooctanesulfonic acid (PFOS) in the blood corresponded with a 56% higher risk for thyroid cancer diagnosis. The PFAS chemicals perfluorononanoic acid (PFNA), perfluorooctylphosphonic acid (PFOPA), and perfluorohexanesulfonic acid (PFHxS) were also found to be associated with thyroid cancer.

“Although preliminary, this is an important study highlighting the risk of thyroid cancer derived from PFAS contamination of water and soil,” said Luca Chiavato, a professor of endocrinology at the University of Pavia in Italy who was not involved with the study.