Decades of Water Contamination in Sweden Linked to 40 Percent Increase in Childhood Asthma Risk

Lund University researchers find a clear link between extreme prenatal PFAS exposure from contaminated drinking water and a 40% increase in pediatric asthma.

By: AXL Media

Published: Apr 10, 2026, 8:33 AM EDT

Source: Information for this report was sourced from EurekAlert!

The Legacy of Firefighting Foam Contamination

For over three decades, residents of Ronneby, Sweden, were unknowingly exposed to high levels of per- and polyfluoroalkyl substances (PFAS) through their municipal drinking water. The contamination, stemming from firefighting foam used during drills at the F17 regiment, was only discovered in 2013. A new study from Lund University has now quantified the long-term health consequences of this exposure, focusing on the most vulnerable population: children who were exposed in the womb. Because PFAS can cross the placenta, maternal consumption of contaminated water directly resulted in fetal exposure during critical stages of development.

Defining the Tipping Point for Respiratory Risk

The research team, led by Annelise Blomberg and Anna Saxne Jöud, analyzed data from 11,488 children born in Blekinge County between 2006 and 2013. By linking maternal residential addresses to water distribution records, the researchers categorized children into exposure groups ranging from low to "very high." The results were stark: while intermediate exposure showed no significant increase in asthma, children in the "very high" exposure group—whose mothers lived at contaminated addresses for five years prior to birth—faced a 40 percent higher risk of developing asthma compared to the control group.

Statistical Rigor and Background Comparison

To ensure the validity of their findings, the researchers adjusted for several confounding factors, including socioeconomic status and maternal smoking during pregnancy. In the low-exposure control group, 16 percent of children developed asthma by age 12. In contrast, that figure rose to 27 percent in the group with the highest PFAS exposure. While the researchers emphasize that this is an observational study and cannot definitively prove PFAS is the sole cause, the clear link persists even after ruling out other common environmental influences.