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Health Capsules
October 2005
Bacteria in Dust Linked to Asthma

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 NIH’s National Institute of Environmental Health Sciences and the University of Iowa.

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.

Definitions iconDefinitions
A chronic disease that causes your airways, the tubes that carry air in and out of your lungs, to get narrower so that less air flows through. Symptoms include wheezing (a whistling sound when you breathe), coughing, chest tightness and trouble breathing.

A type of chemical produced by certain bacteria that is released when they die and disintegrate.

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What is Asthma?:

Asthma and Allergy Prevention:

  Why The Cough?    

Coughs can be a real annoyance, but they serve an important purpose, helping to clear mucus and foreign material like dust from your airways. Most coughs are caused by the common cold, but a violent or persistent cough shouldn’t be ignored.

Coughs lasting 3 weeks or less are most often caused by a cold, but they might be a sign of more serious illness. Pneumonia can cause coughing, high fever, shortness of breath, rapid breathing and chest pain. Congestive heart failure, a condition where the heart can’t pump enough blood, can cause coughing, shortness of breath, difficulty breathing, fatigue and swelling.

“Chronic” coughs lasting 3 weeks or more are often caused by postnasal drip, mucus draining down the back of your throat, from allergies. But they can also be a sign of more serious underlying medical problems. Asthma can cause chronic coughing, chest tightness, wheezing and trouble breathing. Lung cancer causes a chronic cough, chest pain, shortness of breath and other symptoms. Tuberculosis causes a chronic, debilitating cough and chest pain.

Gastroesophageal reflux disease (GERD) can cause chronic coughing, too. When the opening between the esophagus, which carries food from the mouth to the stomach, and the stomach doesn’t close properly, stomach contents can leak back, or reflux, into the esophagus. This can cause heartburn, trouble swallowing, bad breath and a dry cough.

A cough that won’t go away and produces lots of mucus may be a sign of chronic obstructive pulmonary disease (COPD), in which the lung is damaged, making it hard to breathe. Most often caused by smoking, COPD is the 4th leading cause of death.

Cough drops and other treatments may help your coughing, but if you develop a violent cough or one that lasts for more than 3 weeks, see your health provider to make sure it’s not a sign of a serious health problem.

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