Very high maternal exposure to PFAS-contaminated drinking water was associated with a 44% higher rate of childhood asthma.
Most PFAS studies examine background exposure. This Swedish cohort captured an unusually intense real-world exposure from firefighting-foam contamination—and the asthma signal appeared only at the extreme.
Researchers followed 11,488 children in Blekinge County through age 12. They linked maternal addresses during the five years before delivery to municipal water records, identifying 194 children whose mothers had lived throughout that period at addresses receiving highly contaminated water.
- Compared with children at background exposure, the very-high group had a 44% higher asthma rate; in a matched analysis, cumulative incidence was 26.7% versus 16.1%, a 10.6-percentage-point difference.
- Intermediate and high exposure groups showed no increase in asthma, and very high exposure was not associated with early-childhood wheeze.
Exposure was estimated from addresses rather than individual measurements, and 57% of children in the very-high group still lived at contaminated addresses at age three. The study therefore cannot separate prenatal from early-childhood exposure, and its results may not generalize to background PFAS levels or different chemical mixtures.
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The absence of an association at lower exposure categories makes the exposure range and mixture central to interpretation. The signal points to extreme contamination as the setting in which to investigate when early-life PFAS exposure may shape asthma risk. Learn more about PFAS, microplastics, and practical exposure reduction in this episode featuring Dr. Rhonda Patrick.
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