Asthma and wheezing may be triggered by a chemical from bacteria that lurk in household dust, according to a large nationwide study by researchers at the National Institute of Environmental Health Sciences and the University of Iowa.

 

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Scientists studied more than 2,500 dust samples from bedroom, kitchen and living room floors and from bedding and upholstered furniture in 831 homes across the United States. The researchers found that bacterial chemicals called endotoxins—in particular, on bedroom floors and in bedding—are linked to increased breathing problems in adults. Adults in households with higher levels of endotoxin had more diagnosed asthma, asthma symptoms, asthma medication use and wheezing, whether or not they had allergies. The likelihood of recent asthma symptoms was nearly 3 times greater for people exposed to high levels of endotoxin in the bedroom.

Previous studies have shown that house dust contains endotoxin. Pets, pests, humidifiers and kitchen compost bins can all increase the level of endotoxin in a home. Interestingly, early life exposure to household endotoxin protects children against the development of allergies. In contrast, this new research shows that adult exposure to endotoxin raises the risk of asthma. A growing understanding of how asthma is triggered will eventually help in the prevention and treatment of this disease.