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Double blind placebo controlled exposure to molds: exposure system and clinical results

H W Meyer1, K A Jensen, K F Nielsen

  • 1Epidemiological Research Unit, Clinic of Occupational and Environmental Medicine, H:S Copenhagen University Hospital Bispebjerg, Copenhagen NV, Denmark. hmeyer@dadlnet.dk

Indoor Air
|June 2, 2005
PubMed
Abstract

Insights

This study exposed sensitive individuals to mold spores from water-damaged buildings. Short-term exposure to high mold concentrations did not significantly increase symptoms compared to placebo, but larger studies are needed.

Area of Science:

  • Environmental Health
  • Mycology
  • Occupational Medicine

Background:

  • Building-related symptoms (BRS) affect individuals working in water-damaged environments.
  • Mold spores are a common indoor air pollutant linked to various health issues.
  • Previous studies often lack controlled exposure to realistic mold sources.

Purpose of the Study:

  • To develop an experimental setup for controlled human exposure to mold spores.
  • To investigate the clinical effects of mold spore exposure in sensitive individuals with a history of BRS.
  • To assess reactions to Penicillium chrysogenum and Trichoderma harzianum from wet building materials.

Main Methods:

  • Development of a novel exposure system (Particle-Field and Laboratory Emission Cell - P-FLEC).
  • Double-blind, placebo-controlled exposure of 8 sensitive employees to mold spores (P. chrysogenum, T. harzianum) or placebo.
  • Utilized a 9-graded symptom scale to record mucous membrane and other symptoms.

Main Results:

  • A statistically significant increase in mucous membrane symptoms was observed after exposure to T. harzianum and placebo.
  • Borderline increase in mucous membrane symptoms noted after P. chrysogenum exposure.
  • No significant differences in symptoms, objective measurements, or blood samples were found compared to placebo.

Conclusions:

  • The developed P-FLEC system successfully delivered controlled doses of mold spores from building materials.
  • Short-term exposure to high concentrations of P. chrysogenum and T. harzianum did not induce significant reactions in sensitive individuals.
  • The study's small sample size prevents ruling out a mold exposure effect; larger, long-term studies are recommended.

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