Double blind placebo controlled exposure to molds: exposure system and clinical results
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Double blind placebo controlled exposure to molds : exposure system and clinical results. / Meyer, H W; Jensen, K A; Nielsen, K F; Kildesø, Jan; Norn, S; Permin, H; Poulsen, Lars K.; Malling, H J; Gravesen, Søren; Gyntelberg, F.
I: Indoor Air, Bind 15 Suppl 10, 2005, s. 73-80.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Double blind placebo controlled exposure to molds
T2 - exposure system and clinical results
AU - Meyer, H W
AU - Jensen, K A
AU - Nielsen, K F
AU - Kildesø, Jan
AU - Norn, S
AU - Permin, H
AU - Poulsen, Lars K.
AU - Malling, H J
AU - Gravesen, Søren
AU - Gyntelberg, F
PY - 2005
Y1 - 2005
N2 - The objective was to develop an experimental setup for human exposure to mold spores, and to study the clinical effect of this exposure in sensitive subjects who had previously experienced potentially building-related symptoms (BRS) at work. From three water-damaged schools eight employees with a positive histamine release test to Penicillium chrysogenum were exposed double- blinded to either placebo, approximately 600,000 spores/m3 air of P. chrysogenum or approximately 350,000 spores/m3 of Trichoderma harzianum for 6 min on three separate days. A statistically significant rise in symptoms from mucous membranes appeared from the 9-graded symptom scale after exposure to T. harzianum or placebo. Dichotomizing the data, whether the participants experienced at least a two-step rise on the symptom scale or not, gave borderline increase in mucous membrane symptoms after exposure to P. chrysogenum. In conclusion this is, to our knowledge, the first study to successfully conduct a human exposure to a highly controlled dose of fungal material aerosolized directly from wet building materials. This short-term exposure to high concentrations of two different molds induced no more reactions than exposure to placebo in eight sensitive school employees. However, a statistical type II error cannot be excluded because of the small sample size. PRACTICAL IMPLICATIONS: In this double blind, placebo controlled study of mold exposure changes in symptoms, objective measurements and blood samples were small and mostly non-significant, and at the same level as after placebo exposure. The developed exposure system based on the Particle-Field and Laboratory Emission Cell (P-FLEC) makes it possible to deliver a precise and highly controlled dose of mold spores from water-damaged building materials, imitating realistic field exposure conditions. The present experiment is too small to rule out an effect of mold exposure; long-term experimental exposure studies on larger number of subjects are needed.
AB - The objective was to develop an experimental setup for human exposure to mold spores, and to study the clinical effect of this exposure in sensitive subjects who had previously experienced potentially building-related symptoms (BRS) at work. From three water-damaged schools eight employees with a positive histamine release test to Penicillium chrysogenum were exposed double- blinded to either placebo, approximately 600,000 spores/m3 air of P. chrysogenum or approximately 350,000 spores/m3 of Trichoderma harzianum for 6 min on three separate days. A statistically significant rise in symptoms from mucous membranes appeared from the 9-graded symptom scale after exposure to T. harzianum or placebo. Dichotomizing the data, whether the participants experienced at least a two-step rise on the symptom scale or not, gave borderline increase in mucous membrane symptoms after exposure to P. chrysogenum. In conclusion this is, to our knowledge, the first study to successfully conduct a human exposure to a highly controlled dose of fungal material aerosolized directly from wet building materials. This short-term exposure to high concentrations of two different molds induced no more reactions than exposure to placebo in eight sensitive school employees. However, a statistical type II error cannot be excluded because of the small sample size. PRACTICAL IMPLICATIONS: In this double blind, placebo controlled study of mold exposure changes in symptoms, objective measurements and blood samples were small and mostly non-significant, and at the same level as after placebo exposure. The developed exposure system based on the Particle-Field and Laboratory Emission Cell (P-FLEC) makes it possible to deliver a precise and highly controlled dose of mold spores from water-damaged building materials, imitating realistic field exposure conditions. The present experiment is too small to rule out an effect of mold exposure; long-term experimental exposure studies on larger number of subjects are needed.
KW - Adult
KW - Air Pollution, Indoor
KW - Construction Materials
KW - Double-Blind Method
KW - Environmental Exposure
KW - Female
KW - Fungi
KW - Humans
KW - Male
KW - Middle Aged
KW - Placebos
KW - Reproducibility of Results
KW - Sample Size
KW - Sick Building Syndrome
KW - Spores, Fungal
U2 - 10.1111/j.1600-0668.2005.00351.x
DO - 10.1111/j.1600-0668.2005.00351.x
M3 - Journal article
C2 - 15926947
VL - 15 Suppl 10
SP - 73
EP - 80
JO - Indoor Air
JF - Indoor Air
SN - 0905-6947
ER -
ID: 43535926