National Institutes of Health, part of the U.S. Department of Health and Human Services
Asthma (AZ-ma) is a chronic (long-term) lung disease that inflames and narrows the airways. Asthma causes recurring periods of wheezing (a whistling sound when you breathe), chest tightness, shortness of breath, and coughing. The coughing often occurs at night or early in the morning.
To understand asthma, it helps to know how the airways work. The airways are tubes that carry air into and out of your lungs. People who have asthma have inflamed airways. The inflammation makes the airways swollen and very sensitive. The airways tend to react strongly to certain inhaled substances.
When the airways react, the muscles around them tighten. This narrows the airways, causing less air to flow into the lungs. The swelling also can worsen, making the airways even narrower. Cells in the airways might make more mucus than usual. Mucus is a sticky, thick liquid that can further narrow the airways. This chain reaction can result in asthma symptoms. Symptoms can happen each time the airways are inflamed.
Asthma in Children
Asthma affects people of all ages, but it most often starts during childhood. In the United States, more than 25 million people are known to have asthma. About 7 million of these people are children.
A new study looked at whether allergy-causing substances in the home influence kids’ risk of developing asthma. The results provide clues for preventing asthma before it develops.
More than 6 million American children have asthma. Asthma makes airways in the lungs prone to swelling and narrowing. It can cause wheezing, coughing, shortness of breath, and chest tightness.
Dust contains things that can trigger an asthma attack, such as mold, animal dander, or dust mites. Eliminating or reducing these triggers can lessen asthma attacks.
But studies suggest that exposure to these substances early in life may protect children from asthma. To pinpoint how substances in the home influence the development of asthma, NIH-funded researchers began studying newborns in 2005 that had at least one parent with asthma or allergies. Having a parent with asthma or allergies increases the chance of developing asthma.
The researchers collected dust samples from the children’s homes during their first three years of life. They analyzed levels of common allergy triggers in the dust.
About 1 of every 3 children in the study had asthma by age seven. Higher levels of cat, cockroach and mouse substances in the dust samples were linked to a lower risk of having asthma.
The researchers continue to study the children to pinpoint the factors that might reduce asthma risk. “Additional research may help us identify specific targets for asthma prevention strategies,” says study lead Dr. James E. Gern at the University of Wisconsin-Madison.