Per- and polyfluoroalkyl substances (PFAS), often called “forever chemicals,” are a large group of persistent chemicals used in products such as non-stick cookware, water-resistant materials, food packaging, and firefighting foams. Because they can remain in the environment and accumulate in the body over time, researchers are increasingly studying whether early-life exposure may affect children’s health, including cancer risk.
Two recent studies conducted by CLIC researchers and collaborators examined PFAS exposure and childhood cancer in California using complementary approaches:
The first study investigated whether PFAS contamination in public drinking water could help explain geographic patterns of childhood cancer in Los Angeles and Orange Counties. The analysis included 6,554 childhood cancer cases and 13,046 controls born between 2000 and 2019. Researchers used birth addresses to identify children born in areas served by PFAS-contaminated public water systems and accounted for maternal characteristics known to vary geographically, including age, education, race and ethnicity, birthplace, and insurance provider. Some areas with elevated childhood cancer risk overlapped with water districts where PFAS had been detected. However, drinking water contamination did not fully explain these spatial patterns, suggesting that other environmental or location-related factors may also contribute. Certain PFAS compounds were associated with higher odds of rare childhood cancers, including neuroblastoma and retinoblastoma. The contribution of PFAS to geographic cancer patterns appeared stronger among children of US-born mothers than among children of Mexico-born mothers, potentially reflecting differences in tap water consumption.
The second study focused on childhood acute lymphoblastic leukemia (ALL), the most common childhood cancer. Researchers measured PFAS directly in newborn dried blood spots from 125 children later diagnosed with ALL and 219 controls in Los Angeles County. This approach provided a measure of exposure at birth, a critical developmental window. Overall, the findings did not show a consistent association across all PFAS compounds. However, some PFAS measures were higher among children who later developed ALL, suggesting possible exposure-specific associations that require further investigation. Associations appeared more pronounced among non-Hispanic participants, although these stratified analyses were based on small numbers and should be considered exploratory.
Together, the two studies suggest that PFAS exposure warrants further investigation in childhood cancer research, while the current evidence remains uncertain. They also demonstrate the value of combining environmental monitoring data, cancer registries, residential histories, and newborn biological samples to better understand how early-life exposures may contribute to childhood cancer development. By combining innovative exposure assessment methods with diverse population-based data, CLIC researchers are helping to refine the evidence on environmental risk factors for childhood cancer. As evidence accumulates, such studies may help identify preventable risks and support more informed public health and environmental policy decisions.
Citations:
Article 1
Authors: Natalie R Binczewski, Libby M Morimoto, Joseph L Wiemels, David B Richardson, Scott M Bartell, Catherine Metayer, Veronica M Vieira
Published In: J Expo Sci Environ Epidemiol (2026). https://doi.org/10.1038/s41370-026-00850-1
Article 2
Authors: Veronica M. Vieira, Sheng Liu, Libby M. Morimoto, Jeremy Koelmel, Natalie R. Binczewski, Joseph L. Wiemels, Xiaomei Ma, Krystal J. Godri Pollitt, Catherine Metayer
Published In: J Expo Sci Environ Epidemiol (2026). https://doi.org/10.1038/s41370-026-00891-6