The study, conducted by researchers at Lund University, included 11,488 children born in Blekinge, Sweden, between 2006 and 2013. It observed a higher occurrence of asthma among children whose mothers lived all five years before birth at an address with heavily PFAS-contaminated drinking water. According to Annelise Blomberg, a researcher in occupational and environmental medicine at Lund University, the risk of developing asthma was about 40 percent higher among children of mothers with very high PFAS exposure. In contrast, among children whose mothers lived at an exposed address for only one of the five years before birth, no increased occurrence of asthma was seen.
This research is unique because participants were exposed to very high levels of PFAS, according to official sources. The background stems from the discovery in 2013 of high PFAS levels in drinking water in Ronneby municipality, where after fire drills at the F17 regiment, a third of local residents had been exposed to water contaminated by firefighting foam. The contamination had been ongoing for over thirty years, but when the women became pregnant, it was not yet known that drinking water in parts of Blekinge was contaminated. Children were divided into four groups based on the degree of the mother's PFAS exposure at residential addresses, as reported by official sources.
To estimate fetal exposure, researchers used the mothers' residential addresses during the five years before the child's birth, linked to municipal information on water supply. 'High exposure' meant having lived at such an address for at least one of the five years before delivery, according to multiple reports. Children in the study were followed from birth up to twelve years of age, providing a long-term perspective on health outcomes.
The risk of developing asthma was about 40 percent higher among children of mothers with very high PFAS exposure.
The asthma findings revealed a clear dose-response relationship, with very high exposure showing a significant increase. During the follow-up period, 16 percent of children with low exposure developed asthma, compared to 27 percent in the group with very high PFAS exposure, according to multiple reports. A clear association was seen between 'very high exposure' and higher occurrence of asthma, reinforcing the link between prenatal PFAS levels and respiratory health.
PFAS, short for per- and polyfluoroalkyl substances, are commonly known as forever chemicals because of their persistence in the environment. They are a large group of synthetic substances that are very difficult to break down, with some types remaining in the body for a long time, according to multiple reports. PFAS have been linked to a wide range of serious illnesses, including some cancers, and some PFAS have been linked to cancer, birth defects, liver disease, thyroid disease, decreased immunity, hormone disruption, and other serious health problems.
Alarming levels of toxic forever chemicals have been found in the blood of people living in Bentham, a town previously revealed to be contaminated with the UK’s highest recorded level of PFAS, according to major media reports. In May 2024, Ends Report and the Guardian revealed that groundwater in Bentham, North Yorkshire, was contaminated with the highest level of PFAS ever known to be recorded in the UK. This contamination was found on land belonging to Angus Fire, a factory that between 1976 and 2024 legally produced PFAS-containing firefighting foam, as reported by major media.
This would improve our ability to analyze how exposure during different developmental stages can affect children's health.
Blood testing conducted for an ITV documentary revealed that residents and former workers at the Angus Fire factory have 'alarming' levels of PFAS in their blood, according to major media reports. The highest PFAS level in blood recorded in Bentham was 405 ng/ml – more than 200 times greater than the US risk level of 2 ng/ml, as noted by major media. This highest level was recorded in the blood of a former worker at Angus Fire who has asked to remain anonymous. Among them was 34-year-old Stephen Illston, who has a PFAS level of 55 ng/ml, according to major media.
Regulatory gaps are evident, as in the UK, there are no guidelines indicating what constitutes a safe level of PFAS in blood, according to major media reports. In the US, the National Academies of Sciences, Engineering, and Medicine says that if the sum of seven PFAS chemicals in blood is above 2 ng/ml, there is a potential for adverse health effects. Regulators' methods to check for PFAS have been slow, with the EPA typically checking for around 30-40 compounds, while independent researchers find thousands, according to major media reports. A 2022 Guardian analysis found regulators frequently undercounted PFAS levels in water.
Fetal exposure concerns are heightened because PFAS can pass through the placenta, meaning that exposure during pregnancy also means exposure for the fetus, according to multiple reports. New peer-reviewed research shows fetuses likely have much higher levels of PFAS in their blood than previously thought, with a study identifying 42 PFAS compounds in umbilical cord blood samples, as reported by major media. Elevated PFAS levels in mothers is associated with higher infant mortality, low birth weight, obesity later in life, and links to cancer, neurological problems, and cardiovascular disease later in life, according to major media.
The risk of developing asthma was about 40 percent higher among children of mothers with very high PFAS exposure.
Broader health impacts include reproductive problems, with a growing body of research revealing that PFAS are associated with reproductive health problems, including lower sperm count, according to major media reports. This finding comes from a study from Lund University, where researchers studied women who during their pregnancy lived in a part of Blekinge where drinking water was contaminated by firefighting foam. Most people in the United States have been exposed to some PFAS, according to the U.S. Centers for Disease Control and Prevention. Researchers have identified routes of PFAS exposure including drinking water, soil and water at waste sites, firefighting foam, manufacturing facilities, food, food packaging, household products, personal care products, and pesticides.
Industry knowledge has been a point of contention, as companies knew PFAS was 'highly toxic' for decades before it was publicly established in the late 1990s, according to research sources. This historical awareness contrasts with current public health challenges, underscoring the need for transparency and accountability in chemical regulation.
Research limitations and uncertainties are acknowledged by the study authors. Researchers also looked at other factors that could affect the association, noting uncertainty and that they cannot say for sure that the increase is due to PFAS, but they have done their best to remove other influencing factors, according to Anna Saxne Jöud, a researcher at Lund University. A systematic review found no systematic effect of early-life PFAS exposure on language and communication development, with inconclusive findings possibly due to limited validity of test instruments, according to research sources. PFAS are a class of about 15,000 compounds used to make products water-, stain-, and grease-resistant, as reported by major media, though estimates vary, reflecting uncertainty in the scientific understanding of these chemicals.
Future research directions include investigating residents in other exposed locations, according to official sources. Researchers also want to clarify how PFAS can affect lung function, and they will continue to investigate in Ronneby to better pinpoint when exposure was most intense. According to Annelise Blomberg, this would improve our ability to analyze how exposure during different developmental stages can affect children's health.
Implications point to a need for better regulation, monitoring, and public health responses. Similar studies have been done before, but they examined populations with lower PFAS exposure, making this research particularly significant. PFAS are used in a variety of consumer products, with one of their most prolific uses being in firefighting foam, according to major media reports. The substances can occur in many products and foods, including firefighting foam, and everyone is exposed to PFAS to some extent, via a range of products and foods, as noted by multiple reports.
Key unknowns remain, including what specific PFAS compounds are most responsible for the increased asthma risk in children and how PFAS levels in umbilical cord blood correlate with long-term health outcomes beyond infancy. The exact mechanisms by which PFAS exposure during pregnancy leads to higher asthma rates in children are not fully understood, and it is unclear why regulators' methods for checking PFAS typically detect only 30-40 compounds when independent researchers find thousands. The long-term health effects for residents in Bentham, UK, with extremely high PFAS blood levels have not been determined, highlighting ongoing public health concerns.