Prenatal exposure to PFAS, or “forever chemicals,” is linked to acute lymphoblastic leukemia, the most common childhood cancer, in a new study led by UC Irvine.
“Forever chemicals” is a catch-all term for a group of about 14,000 man-made compounds linked to cancers and fertility issues, so named because they do not degrade easily over time and can build up in the body. They’re found in drinking water, nonstick cookware, food and drink packaging and cosmetics.
For this study, researchers examined the newborn blood samples of babies born from 2000 to 2015 in Los Angeles County. The samples were taken from 125 children later diagnosed with acute lymphoblastic leukemia and 219 cancer-free kids.
Seventeen different “forever chemicals,” primarily PFOA and PFOS, were detected in the blood samples, according to the study, which was published in April in the Journal of Exposure Science & Environmental Epidemiology. Elevated levels were linked to an increased likelihood of developing acute lymphoblastic leukemia, and the combined presence of the two chemicals was correlated with an even greater risk of cancer.
Based on these results, the scientists can’t say that forever chemicals cause cancer; rather, they might just contribute to cancer risk.
“This research moves us closer to understanding what babies are exposed to from the very start by directly measuring PFAS present at birth,” said corresponding author Veronica Vieira, a UCI professor of environmental and occupational health. “By capturing exposures during a critical window of development, we are gaining a clearer picture of how environmental contaminants may contribute to childhood cancer risk.”
Because the study was limited to Los Angeles County and had a small sample size, findings “should be interpreted cautiously,” said Rena Jones, an National Institutes of Health researcher who focuses on environmental contaminants. But the study “adds to the growing evidence” that PFAS exposure during pregnancy may contribute to acute lymphoblastic leukemia, said Jones, who was not involved with the study.
Rates of childhood cancers have increased in recent decades in industrialized countries, including the U.S., which suggests environmental factors might be at play, according to the study. Previous research by the same team indicated that elevated levels of PFOA and PFOS also were connected to other childhood cancers, including acute myeloid leukemia and Wilms tumor.
Several factors were associated with higher levels of PFOA and PFOS — children whose parents were older, born in the U.S., received higher education and had private insurance all had higher PFOS exposure. That’s because forever chemicals are commonly found in nonessential or more expensive products, such as Scotchgard, weather-resistant apparel and makeup, Vieira said. High levels of these chemicals can be an “indirect measure of socioeconomic status.”
The good news is that children who were born later had lower PFAS levels, which means some of these more persistent chemicals have been phased out of production. “They’re slowly degrading in the environment and being excreted,” Vieira said. One easy way to reduce PFAS exposure even further is to drink filtered water, she said.
However, researchers identified 26 additional PFAS chemicals, including some compounds that haven’t been well-studied. It’s unclear how toxic these chemicals are, Vieira said.
“The findings point to the need for larger studies that examine a broader range of PFAS, including newer compounds,” Jones said.