Asthma can lead to childhood hospitalizations, missed school days, missed workdays for caregivers, and a lower quality of life for both children and their caregivers. The global prevalence of asthma has increased over the past fifty years. A study published April 9 th in the open-access journal PLOS Medicine by Annelise Blomberg at Lund University, Lund, Sweden and colleagues suggests that high prenatal PFAS exposure is associated with a higher incidence of asthma in childhood.
PFAS (Perfluoroalkyl substances) are widespread synthetic chemicals that impact the immune system and may play a role in the development of asthma. Previous epidemiological studies of PFAS and asthma only investigated low exposure levels and had inconclusive results. Due to decades-long contamination of a municipal waterworks in Ronneby, Sweden, researchers were able to study the impacts of high PFAS exposure. They accessed a register-based open cohort of all children born in Blekinge County between 2006 and 2013, including Ronneby. The researchers then linked maternal addresses during the exposure period to water distribution records to estimate prenatal exposure, and used asthma diagnosis data from the National Patient Register to assess individual asthma outcomes and prenatal exposure levels.
The researchers found that very high prenatal PFAS exposure was associated with a higher incidence of asthma in childhood. Future studies are needed to better understand exposure-response relationships and to address potential confounding variables, such as exposure beyond the prenatal period into early-childhood, exposure to other environmental contaminants or smoking among household members.
According to the authors, “PFAS contamination is a major source of high environmental exposure globally, and evidence from Ronneby offers important insights into the potential health effects of such contamination in affected communities. These results point to a substantial and previously unrecognized public health consequence of PFAS contamination.”
Blomberg adds, “We found that children whose mothers were exposed to very high levels of PFAS during pregnancy had a substantially higher incidence of clinically diagnosed asthma. The association was not observed at lower exposure levels, which may help explain why previous studies in general populations have reported mixed results.”
“ Most previous research has examined populations exposed only to background levels of PFAS. In Ronneby, drinking water contamination resulted in exposure levels hundreds of times higher than the general population. This allowed us to evaluate potential health effects across a much broader exposure range.”
“ Communities around the world have been affected by PFAS contamination from aqueous film-forming foams and other industrial sources. Our findings suggest that very high prenatal exposure may have lasting consequences for children’s respiratory health. At the same time, replication in other highly exposed populations will be important to confirm these results.”
In your coverage, please use this URL to provide access to the freely available paper in PLOS Medicine : https://plos.io/4tZWh7W
Citation: Blomberg AJ, Nielsen C, Borgström Bolmsjö B, Bind M-A, Hartman L, Saxne Jöud A (2026) Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and incidence of asthma and wheeze in childhood: A register-based cohort study in Ronneby, Sweden. PLoS Med 23(4): e1004659. https://doi.org/10.1371/journal.pmed.1004659
Author countries : Sweden, Denmark, United States of America
Funding: This work was funded by the European Union’s Horizon Europe program under the Marie Skłodowska-Curie Postdoctoral Fellowships ( https://marie-sklodowska-curie-actions.ec.europa.eu/actions/postdoctoral-fellowships ; grant number 101058697 to AJB) and the Swedish Research Council for Health, Working Life and Welfare (FORTE, https://forte.se/en ; grant number 2020-00112 to ASJ and 2024-00748 to AJB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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Competing interests: The authors have declared that no competing interests exist.