A first-of-its-kind study has found that in US communities where drinking water is contaminated with per- and polyfluoroalkyl substances (PFAS), there’s also an increased incidence of some cancers, with the so-called “forever chemicals” potentially contributing to over 6,800 cancer cases in the country each year.
PFAS appear to be everywhere: in the air, in the rain, and according to recent research, in the drinking water of up to 7 percent of people in the US. With existing studies linking PFAS exposure to health problems ranging from sleep disturbance to liver damage – although there’s still a lot we don’t know – a team of researchers from the Keck School of Medicine has now sought to discover more about their relationship with cancer.
To do so, the researchers took county-level data on cancer incidence between 2016 and 2021 plus data on PFAS levels in public drinking water systems. They used statistical modeling to determine if there was any association between the two.
The results indicated that “PFAS in drinking water was associated with increased cancer incidence in the digestive, endocrine, oral cavity/pharynx, and respiratory systems,” the team wrote in the paper detailing their results.
The strongest association they discovered in their results was between a specific kind of PFAS, called perfluorobutanesulfonic acid (PFBS), and oral cavity and pharyngeal cancers; communities exposed to PFBS experienced a 33 percent higher incidence of these cancers. Exposure to PFAS was also associated with a higher incidence of leukemia in males, and of thyroid, oral and pharyngeal, and soft tissue cancers in females.
Based on these associations, the team estimated that PFAS could be contributing to between 4,626 and 6,864 incidences of cancer in the US each year.
However, it’s important to note here that association is not the same thing as causation. While the researchers found some associations between PFAS in drinking water and certain cancers to be statistically significant, meaning there could be a causal relationship between the two, that doesn’t necessarily mean there is one.
Nonetheless, it’s also worth mentioning that the study authors did control for some of the other factors that can influence cancer risk, like age, sex, obesity, and smoking rates. Taking those out of the equation makes it easier for them to confidently suggest that PFAS might be the responsible party – though more research is required before “might” could become “is”.
“These findings allow us to draw an initial conclusion about the link between certain rare cancers and PFAS,” said the study’s first author Shiwen Li in a statement. “This suggests that it’s worth researching each of these links in a more individualized and precise way.”
The study is published in the Journal of Exposure Science and Environmental Epidemiology.
