Headshot Credit: Jenny Leyman Photography<\/em>
<\/figcaption><\/figure>\n\u201cHowever, our results may be relevant for clinicians who are working in populations that have had high exposures to PFAS, and particularly high exposures via firefighting foam,\u201d Blomberg said.<\/p>\n
In a register-based cohort study, Blomberg and <\/b>colleagues assessed 11,488 children born in Blekinge County, Sweden, between 2006 and 2013 to determine how prenatal PFAS exposure impacts the incidence of asthma and wheeze in childhood.<\/p>\n
\u201cIn 2013, high levels of PFAS were detected at one of the two municipal water sources in the town of Ronneby, Sweden,\u201d Blomberg told Healio.<\/p>\n
Specifically, the researchers wrote, aqueous film-forming foam running off from a military airfield nearby had contaminated the water source. PFAS concentrations included 10,380 ng\/L for the contaminated source and 48 ng\/L for the non-contaminated source. <\/p>\n
\u201cPFAS cross the placenta, transferring from a pregnant mother to her unborn child,\u201d she continued. \u201cThis prenatal PFAS exposure may impact the developing immune system. However, previous research on asthma has been inconclusive and has not included a population with high levels of exposure.\u201d<\/p>\n
Prenatal PFAS exposure, found by linking maternal address history to water distribution records, was divided into four groups: very high (n = 194), high (n = 479), intermediate (n = 1,591) and background (n = 9,224).<\/p>\n
\u201cPrenatal exposure was categorized as \u2018very high\u2019 if the child\u2019s mother lived at an address in Ronneby supplied with highly contaminated water for all 5 years preceding the year of delivery; \u2018high\u2019 if she lived at an address in Ronneby with contaminated water for at least one of those 5 years; \u2018intermediate\u2019 if she lived in Ronneby during that period but never at an address supplied with highly contaminated water; and \u2018background\u2019 if she did not live in Ronneby during the 5 years preceding the year of delivery,\u201d Blomberg and colleagues wrote.<\/p>\n
Children were followed until age 12 years or Dec. 31, 2022, and at this point, 18% had a wheeze diagnosis, 17% had an asthma diagnosis and 13% had \u201cat least one asthma diagnosis or dispensation of asthma-related prescription drugs after age 36 months (3+ years),\u201d according to the study.<\/p>\n
In a Cox proportional hazards model adjusted for several individual-level confounders (maternal smoking in early pregnancy, maternal age at delivery, parity, child sex, parental asthma and socioeconomic factors), researchers found a significant link between very high prenatal PFAS exposure and elevated asthma incidence vs. background exposure (HR = 1.44; 95% CI, 1.08-1.92). <\/p>\n
This exposure level was also linked to higher incidence of asthma (3+) vs. background prenatal PFAS exposure (HR = 1.59; 95% CI, 1.14-2.21).<\/p>\n
\u201cOur study identified a strong association between very high prenatal PFAS exposure and asthma in childhood,\u201d Blomberg said. \u201cThis was surprising to us because results from previous studies of PFAS and asthma have been mixed. Some studies have observed a link between PFAS and asthma, but many have not. <\/p>\n
\u201cHowever, most previous studies only included populations with low levels of PFAS exposure, while our study investigated effects in a population that included children who had been exposed at very high levels from PFAS contamination in their drinking water,\u201d she told Healio.<\/p>\n
When evaluating the sets of children with high and intermediate prenatal PFAS exposure, Blomberg and colleagues reported no link to asthma incidence.<\/p>\n
For wheeze, the intermediate, high and very high prenatal PFAS exposure groups were not linked to greater wheeze incidence vs. background exposure.<\/p>\n
In a secondary analysis that included the children with very high prenatal PFAS exposure and 582 matched background-exposed children, the very high-exposed cohort had a greater estimated cumulative incidence of asthma (26.7% vs. 16.1%) and asthma (3+) (21.5% vs. 11.1%).<\/p>\n
\u201cThis is one of the first studies to observe a link between high PFAS exposures and asthma, and future studies are needed to verify our results in other populations,\u201d Blomberg told Healio.<\/p>\n
For more information:<\/h2>\n
Annelise J. Blomberg, ScD,<\/b> can be reached at annelise.blomberg@med.lu.se. <\/p>\n\n
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