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Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and incidence of asthma and wheeze in childhood : A register-based cohort study in Ronneby, Sweden

Blomberg, Annelise J LU orcid ; Nielsen, Christel LU orcid ; Borgström Bolmsjö, Beata LU ; Bind, Marie-Abèle ; Hartman, Linda LU orcid and Saxne Jöud, Anna LU orcid (2026) In PLoS Medicine 23(4). p.1-19
Abstract

BACKGROUND: Early-life exposure to per- and polyfluoroalkyl substances (PFAS) may impact the developing lungs and immune system and increase the risk of childhood asthma, but no studies have been conducted in a high-exposed population. The objective of this study was to estimate associations between prenatal PFAS exposure and childhood incidence of asthma and wheeze in Blekinge County, Sweden, where a subset of residents in the city of Ronneby was exposed to PFAS from drinking water contaminated by aqueous film-forming foam (AFFF).

METHODS AND FINDINGS: We constructed a register-based open cohort of 11,488 children born in Blekinge county between 2006 and 2013 and followed each individual from birth until age 12 or December 31,... (More)

BACKGROUND: Early-life exposure to per- and polyfluoroalkyl substances (PFAS) may impact the developing lungs and immune system and increase the risk of childhood asthma, but no studies have been conducted in a high-exposed population. The objective of this study was to estimate associations between prenatal PFAS exposure and childhood incidence of asthma and wheeze in Blekinge County, Sweden, where a subset of residents in the city of Ronneby was exposed to PFAS from drinking water contaminated by aqueous film-forming foam (AFFF).

METHODS AND FINDINGS: We constructed a register-based open cohort of 11,488 children born in Blekinge county between 2006 and 2013 and followed each individual from birth until age 12 or December 31, 2022. Maternal address history was linked to water distribution records to create a categorical proxy variable for prenatal PFAS exposure from drinking water. We identified incident cases of wheeze and asthma from administrative health records and estimated hazard ratios (HRs) using Cox proportional hazards models adjusted for individual-level confounders, including maternal smoking in early pregnancy, maternal age at delivery, parity, child sex, parental asthma, and socioeconomic factors. As a secondary analysis, we applied a Rubin Causal Model (RCM) analysis to estimate the average marginal effect of prenatal PFAS exposure on wheeze and asthma among the very highly-exposed population, using a matched dataset of very-high and background-exposed individuals balanced on measured confounders. Overall, 18% of children were diagnosed with wheeze and 17% with asthma during follow-up. Very high prenatal PFAS exposure was associated with incidence of asthma (HR: 1.44, 95% CI [1.08, 1.92]), whereas no associations were observed for the high or intermediate exposure groups or for wheeze. In the RCM analysis, the estimated cumulative incidence of asthma was 16.1% in the background-exposed group and 26.7% in the very highly exposed group (Fisherian p < 0.001). Study limitations include reliance on an address-based categorical proxy for prenatal PFAS exposure, which likely results in non-differential exposure misclassification and limits the ability to distinguish prenatal from early-childhood exposure effects.

CONCLUSIONS: In this study, very high prenatal PFAS exposure was associated with a higher incidence of childhood asthma. Although these results should be replicated, they suggest an important public health impact of AFFF-associated PFAS contamination.

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; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Asthma, Wheeze, per- and polyfluoroalkyl substances, PFAS, Prenatal exposure, aqueous film-forming foam (AFFF), Epidemiology
in
PLoS Medicine
volume
23
issue
4
article number
e1004659
pages
1 - 19
publisher
Public Library of Science (PLoS)
external identifiers
  • pmid:41955175
  • scopus:105035471096
ISSN
1549-1676
DOI
10.1371/journal.pmed.1004659
language
English
LU publication?
yes
additional info
Copyright: © 2026 Blomberg et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
id
135662f7-1b95-4141-8f7b-7ff2a60cd599
date added to LUP
2026-04-10 15:05:06
date last changed
2026-06-08 04:01:14
@article{135662f7-1b95-4141-8f7b-7ff2a60cd599,
  abstract     = {{<p>BACKGROUND: Early-life exposure to per- and polyfluoroalkyl substances (PFAS) may impact the developing lungs and immune system and increase the risk of childhood asthma, but no studies have been conducted in a high-exposed population. The objective of this study was to estimate associations between prenatal PFAS exposure and childhood incidence of asthma and wheeze in Blekinge County, Sweden, where a subset of residents in the city of Ronneby was exposed to PFAS from drinking water contaminated by aqueous film-forming foam (AFFF).</p><p>METHODS AND FINDINGS: We constructed a register-based open cohort of 11,488 children born in Blekinge county between 2006 and 2013 and followed each individual from birth until age 12 or December 31, 2022. Maternal address history was linked to water distribution records to create a categorical proxy variable for prenatal PFAS exposure from drinking water. We identified incident cases of wheeze and asthma from administrative health records and estimated hazard ratios (HRs) using Cox proportional hazards models adjusted for individual-level confounders, including maternal smoking in early pregnancy, maternal age at delivery, parity, child sex, parental asthma, and socioeconomic factors. As a secondary analysis, we applied a Rubin Causal Model (RCM) analysis to estimate the average marginal effect of prenatal PFAS exposure on wheeze and asthma among the very highly-exposed population, using a matched dataset of very-high and background-exposed individuals balanced on measured confounders. Overall, 18% of children were diagnosed with wheeze and 17% with asthma during follow-up. Very high prenatal PFAS exposure was associated with incidence of asthma (HR: 1.44, 95% CI [1.08, 1.92]), whereas no associations were observed for the high or intermediate exposure groups or for wheeze. In the RCM analysis, the estimated cumulative incidence of asthma was 16.1% in the background-exposed group and 26.7% in the very highly exposed group (Fisherian p &lt; 0.001). Study limitations include reliance on an address-based categorical proxy for prenatal PFAS exposure, which likely results in non-differential exposure misclassification and limits the ability to distinguish prenatal from early-childhood exposure effects.</p><p>CONCLUSIONS: In this study, very high prenatal PFAS exposure was associated with a higher incidence of childhood asthma. Although these results should be replicated, they suggest an important public health impact of AFFF-associated PFAS contamination.</p>}},
  author       = {{Blomberg, Annelise J and Nielsen, Christel and Borgström Bolmsjö, Beata and Bind, Marie-Abèle and Hartman, Linda and Saxne Jöud, Anna}},
  issn         = {{1549-1676}},
  keywords     = {{Asthma; Wheeze; per- and polyfluoroalkyl substances; PFAS; Prenatal exposure; aqueous film-forming foam (AFFF); Epidemiology}},
  language     = {{eng}},
  month        = {{04}},
  number       = {{4}},
  pages        = {{1--19}},
  publisher    = {{Public Library of Science (PLoS)}},
  series       = {{PLoS Medicine}},
  title        = {{Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and incidence of asthma and wheeze in childhood : A register-based cohort study in Ronneby, Sweden}},
  url          = {{http://dx.doi.org/10.1371/journal.pmed.1004659}},
  doi          = {{10.1371/journal.pmed.1004659}},
  volume       = {{23}},
  year         = {{2026}},
}