home Journal club Potential interesting new (alas not freely available) paper on microbial exposure and asthma/allergy

Potential interesting new (alas not freely available) paper on microbial exposure and asthma/allergy

There is a new paper in the New England Journal of Medicine that looks to be of relevance to those interested in built environment microbiology.  Unfortunately the paper is not freely available and I do not have access to it right now.  But there is a summary available (from the authors/journal):

Exposure to Environmental Microorganisms and Childhood Asthma

Markus J. Ege, M.D., Melanie Mayer, Ph.D., Anne-Cécile Normand, Ph.D., Jon Genuneit, M.D., William O.C.M. Cookson, M.D., D.Phil., Charlotte Braun-Fahrländer, M.D., Dick Heederik, Ph.D., Renaud Piarroux, M.D., Ph.D., and Erika von Mutius, M.D. for the GABRIELA Transregio 22 Study Group

N Engl J Med 2011; 364:701-709February 24, 2011

BACKGROUND

Children who grow up in environments that afford them a wide range of microbial exposures, such as traditional farms, are protected from childhood asthma and atopy. In previous studies, markers of microbial exposure have been inversely related to these conditions.

METHODS

In two cross-sectional studies, we compared children living on farms with those in a reference group with respect to the prevalence of asthma and atopy and to the diversity of microbial exposure. In one study – PARSIFAL (Prevention of Allergy – Risk Factors for Sensitization in Children Related to Farming and Anthroposophic Lifestyle) – samples of mattress dust were screened for bacterial DNA with the use of single-strand conformation polymorphism (SSCP) analyses to detect environmental bacteria that cannot be measured by means of culture techniques. In the other study – GABRIELA (Multidisciplinary Study to Identify the Genetic and Environmental Causes of Asthma in the European Community [GABRIEL] Advanced Study) – samples of settled dust from children’s rooms were evaluated for bacterial and fungal taxa with the use of culture techniques.

RESULTS

In both studies, children who lived on farms had lower prevalences of asthma and atopy and were exposed to a greater variety of environmental microorganisms than the children in the reference group. In turn, diversity of microbial exposure was inversely related to the risk of asthma (odds ratio for PARSIFAL, 0.62; 95% confidence interval [CI], 0.44 to 0.89; odds ratio for GABRIELA, 0.86; 95% CI, 0.75 to 0.99). In addition, the presence of certain more circumscribed exposures was also inversely related to the risk of asthma; this included exposure to species in the fungal taxon eurotium (adjusted odds ratio, 0.37; 95% CI, 0.18 to 0.76) and to a variety of bacterial species, including Listeria monocytogenes, bacillus species, corynebacterium species, and others (adjusted odds ratio, 0.57; 95% CI, 0.38 to 0.86).

CONCLUSIONS

Children living on farms were exposed to a wider range of microbes than were children in the reference group, and this exposure explains a substantial fraction of the inverse relation between asthma and growing up on a farm. (Funded by the Deutsche Forschungsgemeinschaft and the European Commission.)

The collaborators in GABRIELA (Multidisciplinary Study to Identify the Genetic and Environmental Causes of Asthma in the European Community [GABRIEL] Advanced Study) are listed in the Supplementary Appendix, available at NEJM.org.

Supported by grants from Deutsche Forschungsgemeinschaft (SFB Transregio 22 Pulmonary Allergies, Project A1) and the European Commission (LSH-2004-1.2.5-1 and QLRT 1999-01391).

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.

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