Risk mitigation
The half-life of PFAS in the human body is about 3-7 years, said Dr. Goodrich.
“There’s not much you can do once they’re in there,” he said. “So, the focus needs to be on preventing the exposure in the first place.”
People can limit exposure by avoiding water contaminated with PFAS or filtering it out, Dr. Goodrich said. He recommended avoiding fish from contaminated waterways and nonstick cookware. The Environmental Protection Agency has more detailed recommendations.
But giving patients individualized recommendations is difficult, said Vincent Chen, MD, MS, a clinical instructor in gastroenterology at the University of Michigan, Ann Arbor, who was not involved in the study. Most clinicians don’t know their patients’ PFOS levels.
“It’s not that easy to get a test,” Dr. Chen told this news organization.
People can also mitigate their risk factors for hepatocellular carcinoma, such as a poor diet, a lack of exercise, and smoking, said Dr. Goodrich.
The researchers found that patients with hepatocellular carcinoma were more likely to be overweight and have diabetes, and PFOS was associated with higher fasting glucose levels. This raises the possibility that PFOS increases the risk for hepatocellular carcinoma by causing diabetes and obesity.
Dr. Goodrich and his colleagues tried to address this question by adjusting for baseline body mass index (BMI) and diabetes diagnosis in their statistical analysis.
After adjusting for BMI, they found that the association between PFOS and hepatocellular carcinoma diminished to a threefold risk (OR, 2.90; 95% CI, 0.78-10.00) and was no longer statistically significant (P = .11).
On the other hand, adjusting for diabetes did not change the significance of the relationship between PFOS and the cancer (OR, 5.7; 95% CI, 1.10-30.00; P = .04).
The sample size was probably too small to adequately tease out this relationship, Dr. Chen said. Still, he said, “I thought it was a very, very important study.”
The levels of PFOS found in the blood of Americans has been declining since the 1999-2000 NHANES, Dr. Chen pointed out. But that’s not as reassuring as it sounds.
“The problem is that if you put a regulation limiting the use of one PFAS, what people can do is just substitute with another PFAS or another molecule, which for all we know could be equally harmful,” Dr. Chen said.
Funding was provided by the Southern California Environmental Health Science Center supported by the National Institutes of Health. Dr. Goodrich and Dr. Chen report no relevant financial relationships.
A version of this article first appeared on Medscape.com.