Hormone replacement therapy and the risk of asthma attacks: population-based cohort study
File(s)
Published version (early view)
Author(s)
Lee, Bohee
Anpalagan, Hareshwaran
Wong, Ernie
Tan, Tricia
Bloom, Chloe
Type
Journal Article
Abstract
Background
Women experience higher rates and greater severity of asthma after puberty, suggesting that sex hormones play a key role in airway disease. Hormone replacement therapy (HRT), which acutely alters circulating sex hormone levels, provides a useful model to examine their effects on asthma attacks. We sought to examine the association between HRT use and asthma attacks.
Methods
We obtained a cohort of women with asthma, aged 45 to 60 years, using nationwide U.K. primary care health records linked to hospital and mortality data, 2004-2020, to compare HRT-users to non-users. We applied inverse-probability of treatment weighting and Cox proportional
hazards, accounting for demographics, asthma severity and comorbidities; stratifying by potential modifiers: body mass index (BMI), blood eosinophil count, smoking and HRT-type (oestrogen-only, progesterone-only and combined).
Results
182,010 women were eligible for the study, of whom 9,663 were incident HRT users and 172,347 were non-users. Median age was 52 years (IQR: 50-55 years). HRT-users and non-users were broadly similar in terms of BMI, smoking history but non-users had slightly higher proportions residing in more deprived areas, with more comorbidities, higher reliever use and asthma attacks in the year before study entry, but lower use of preventer inhalers. After applying weighting, there was no association found between HRT use and asthma attacks (weighted-HR 0.97, 95% CI 0.90-1.04). There was no modification of that association by blood eosinophil level, BMI, smoking history or HRT-type.
Conclusion
Hormone replacement therapy use is not associated with asthma attacks
in women with established asthma aged 45 to 60 years old.
Women experience higher rates and greater severity of asthma after puberty, suggesting that sex hormones play a key role in airway disease. Hormone replacement therapy (HRT), which acutely alters circulating sex hormone levels, provides a useful model to examine their effects on asthma attacks. We sought to examine the association between HRT use and asthma attacks.
Methods
We obtained a cohort of women with asthma, aged 45 to 60 years, using nationwide U.K. primary care health records linked to hospital and mortality data, 2004-2020, to compare HRT-users to non-users. We applied inverse-probability of treatment weighting and Cox proportional
hazards, accounting for demographics, asthma severity and comorbidities; stratifying by potential modifiers: body mass index (BMI), blood eosinophil count, smoking and HRT-type (oestrogen-only, progesterone-only and combined).
Results
182,010 women were eligible for the study, of whom 9,663 were incident HRT users and 172,347 were non-users. Median age was 52 years (IQR: 50-55 years). HRT-users and non-users were broadly similar in terms of BMI, smoking history but non-users had slightly higher proportions residing in more deprived areas, with more comorbidities, higher reliever use and asthma attacks in the year before study entry, but lower use of preventer inhalers. After applying weighting, there was no association found between HRT use and asthma attacks (weighted-HR 0.97, 95% CI 0.90-1.04). There was no modification of that association by blood eosinophil level, BMI, smoking history or HRT-type.
Conclusion
Hormone replacement therapy use is not associated with asthma attacks
in women with established asthma aged 45 to 60 years old.
Date Issued
2026-04-23
Date Acceptance
2026-03-05
Citation
ERJ Open Research, 2026, pp.01599-2025
ISSN
2312-0541
Publisher
European Respiratory Society
Start Page
01599
End Page
2025
Journal / Book Title
ERJ Open Research
Copyright Statement
© The authors 2026 This version is distributed under the terms of the Creative Commons Attribution Licence 4.0.
License URL
Publication Status
Published online
Date Publish Online
2026-04-23