Environmental Allergens Pose Greater Asthma Risk for Older Adults

New research suggests older adults are more vulnerable to asthma-promoting effects of environmental estrogens.

Published on Feb. 27, 2026

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A new study presented at the American Academy of Allergy, Asthma & Immunology (AAAAI) 2026 Annual Meeting found that older adults may be more sensitive to the asthma-promoting impact of environmental estrogens compared to younger individuals. The study, which used a mouse model, showed that older mice exposed to the environmental estrogen bisphenol S and cat dander had significantly higher levels of leukocytes, neutrophils, and antibodies compared to younger mice exposed to the same stimuli. The findings suggest that environmental estrogen exposure could represent a modifiable risk factor for asthma exacerbations in older adults, though more research is needed to confirm the mechanisms in humans.

Why it matters

Chronic asthma is more common and associated with higher prevalence, morbidity, and mortality in older adults compared to younger individuals. Understanding the age-specific pathways by which environmental factors like estrogens impact asthma is important given the high burden of asthma-related illness in the older adult population.

The details

The study used a mouse model to compare the effects of exposure to the environmental estrogen bisphenol S and cat dander in older mice (over 18 months) versus younger mice (6-8 weeks). After 4 weeks of bisphenol S exposure and 2 weeks of nasal cat dander exposure, the researchers found significantly higher levels of total leukocytes, neutrophils, and antibodies (IgG1 and IgG2a) in the older mice compared to the younger mice. Analysis of cytokine levels in the lungs is still ongoing.

  • The mice were exposed to bisphenol S in drinking water for 4 weeks.
  • The mice were exposed to cat dander extract nasally every other day for 2 weeks, starting 2 weeks after the bisphenol S introduction.
  • Tissue samples were collected 24 hours after the last nasal exposure to cat dander.

The players

Terumi Midoro-Horiuti

The senior author of the study and a professor of pediatrics at the University of Texas Medical Branch in Galveston.

Arianne K. Baldomero

A pulmonologist and assistant professor of medicine at the University of Minnesota in Minneapolis who was not involved in the study.

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What they’re saying

“Airway hyperresponsiveness is significantly increased in older adults with environmental estrogen exposure, but not in younger adults.”

— Terumi Midoro-Horiuti, Professor of Pediatrics (Medscape Medical News)

“If similar mechanisms are confirmed in humans, environmental estrogen exposure could represent a modifiable risk factor for asthma exacerbations in older adults.”

— Arianne K. Baldomero, Pulmonologist and Assistant Professor of Medicine (Medscape Medical News)

What’s next

Further investigation of the mechanism behind the different responses to environmental estrogen exposure between older and younger adults is ongoing.

The takeaway

This study suggests older adults may be more vulnerable to the asthma-promoting effects of environmental estrogens compared to younger individuals, highlighting the need for more research to understand age-specific pathways and potential interventions to reduce asthma burden in the older adult population.