A new study analyzing over 40,000 cases and controls suggests potential associations between prenatal exposure to per- and polyfluoroalkyl substances in drinking water and an increased risk of certain childhood cancers.
Published in Environmental Epidemiology, the researchers examined data from 10,220 children diagnosed with cancer between ages 0-15 years in California from 2000 to 2015 and 29,974 healthy controls. Using geocoded maternal birth addresses linked to public water system data from the Third Unregulated Contaminant Monitoring Rule (UCMR3) (2013–2015), they estimated maternal serum perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) levels via a pharmacokinetic model. Predicted maternal serum concentrations ranged from background (5 ng/mL PFOS and 2 ng/mL PFOA) to 22.89 ng/mL and 6.66 ng/mL, respectively. Logistic regression models adjusted for birth year, sex, maternal age, race/ethnicity, education, and insurance type were used to assess cancer risk per doubling of exposure.
The study found suggestive associations between PFOS exposure and nonastrocytoma gliomas (AOR = 1.26; 95% CI: 0.99, 1.60), acute myeloid leukemia (AOR = 1.14; 95% CI: 0.94, 1.39), Wilms tumor (AOR = 1.15; 95% CI: 0.96, 1.38), and noncentral system embryonal tumors (AOR = 1.07; 95% CI: 0.98, 1.17). PFOA exposure showed a suggestive association with non-Hodgkin lymphoma (AOR = 1.19; 95% CI: 0.95, 1.49). Among children of Mexico-born mothers, PFOS and PFOA exposure were linked to a higher risk of Wilms tumor (AORPFOS = 1.52; 95% CI: 1.06, 2.18 and AORPFOA = 1.59; 95% CI: 1.12, 2.24) and noncentral system embryonal tumors (AORPFOS = 1.24; 95% CI: 1.03, 1.50 and AORPFOA = 1.19; 95% CI: 0.98, 1.45).
While the study provides one of the first large-scale analyses of childhood cancer risk from per- and polyfluoroalkyl substances (PFAS) exposure via drinking water, confidence intervals often included one, requiring cautious interpretation. The researchers note that prior epidemiologic studies on PFAS and childhood cancer risk have been limited. Given that PFOS and PFOA have been detected in public water systems nationwide, the Environmental Protection Agency established a maximum contaminant level of 4 ng/L for both in April 2024. The International Agency for Research on Cancer has classified PFOA as Group 1 ("carcinogenic to humans") and PFOS as Group 2B ("possibly carcinogenic to humans").
Limitations include the use of modeled rather than direct maternal serum measurements, potential exposure misclassification due to the reliance on UCMR3 data from 2013–2015 for children born between 2000 and 2015, and unaccounted environmental or genetic factors. Additionally, exposure assignments were based on birth address only; if mothers moved during pregnancy, this could affect exposure assessment. Future research should incorporate direct maternal serum measurements and broader population studies.
"This is one of the first studies to assess prenatal exposures to PFOS or PFOA and the associations with the incidence of multiple childhood cancer types by specifically assessing the epidemiologic impacts of exposures to PFAS via drinking water," said lead author Natalie Binczewski from the Department of Environmental and Occupational Health, Joe C. Wen School of Population and Public Health, University of California.
The researchers conclude that their results suggest associations between predicted prenatal maternal PFAS serum concentrations and some childhood cancers, though they note that additional studies are warranted to investigate these relationships further.
The research was supported by NIH grant R01 ES032196, and the authors reported no conflicts of interest.
