Childhood Exposure to Dust May Protect Against Asthma

In particular, endotoxin exposure appears to play a role

MONDAY, April 24 (HealthDay News) -- Early exposure to dust containing the endotoxin or extracellular polysaccharides from microbes, including fungi, appears to bestow protection against developing asthma later in life, according to a study published online April 5 in the Journal of Allergy and Clinical Immunology.

Jeroen Douwes, Ph.D., of Utrecht University in the Netherlands, and colleagues measured microbial exposure among a sample of children at the age of three months, all of whom had atopic mothers. They then measured the development of atopic sensitization and physician-diagnosed asthma and wheeze during the first four years of life. Information on morbidity was gathered using annual questionnaires.

Microbial levels in mattresses were low, and there was no association with serum IgE levels, asthma or wheeze. However, there was an inverse association between contaminants in the dust from living room floors and physician-diagnosed asthma. In particular, endotoxin and extracellular polysaccharides from Penicillium and Aspergillus were associated with a lower asthma risk (odds ratio 0.40 and 0.42, respectively). Children in the high-exposure group also reported consistently less persistent wheeze.

Although "our findings need confirmation at older ages, they provide evidence from a prospective cohort study that noninfectious microbial exposure at a very young age might protect against asthma. The underlying mechanisms are not clear and require further study," the authors conclude.

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Jane Parry

Jane Parry

Updated on April 24, 2006

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