Effect of formaldehyde on asthmatic response to inhaled allergen challenge

Environ Health Perspect. 2007 Feb;115(2):210-4. doi: 10.1289/ehp.9414. Epub 2006 Nov 7.


Background: Exposure to formaldehyde may lead to exacerbation of asthma.

Objectives: Our aim in this study was to investigate whether exposure to a low level (500 microg/m(3)) of formaldehyde enhances inhaled allergen responses.

Methods: Twelve subjects with intermittent asthma and allergy to pollen were exposed, at rest, in a double-blind crossover study to either formaldehyde or purified air for 60 min. The order of exposure to formaldehyde and air-only was randomized, and exposures were separated by 2 weeks. We also performed an allergen inhalation challenge after each exposure. Airway responsiveness to methacholine and lower airway inflammation (induced sputum) were assessed 8 hr after allergen challenge.

Results: The median dose of allergen producing a 15% decrease in forced expiratory volume in 1 sec (PD(15)FEV(1)) was 0.80 IR (index of reactivity) after formaldehyde exposure compared with 0.25 IR after air-only exposure (p = 0.06). Formaldehyde exposure did not affect allergen-induced increase in responsiveness to methacholine (p = 0.42). We found no formaldehyde-associated effect on the airway inflammatory response, in particular the eosinophilic inflammatory response, induced by the allergen challenge 8 hr before.

Conclusion: In this study, exposure to 500 microg/m(3) formaldehyde had no significant deleterious effect on airway allergen responsiveness of patients with intermittent asthma; we found a trend toward a protective effect.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Air Pollutants / toxicity*
  • Allergens / immunology
  • Asthma / diagnosis
  • Asthma / etiology*
  • Asthma / immunology
  • Female
  • Formaldehyde / toxicity*
  • Humans
  • Inhalation Exposure
  • Male
  • Respiratory Function Tests
  • Sputum / chemistry


  • Air Pollutants
  • Allergens
  • Formaldehyde