Asthma in Women
Asthma in Pregnancy

Definition and Causes of Asthma

Twenty percent of the U.S. population has allergies or asthma (6).

Asthma is a disease of chronic inflammation of the airways (the tubes bringing air to the lungs). The inflammation makes breathing difficult. How asthma affects a person fluctuates with a person's various environmental and medical conditions. Asthma can be life-threatening. It is not contagious. Symptoms can start at any age.

Asthma is defined as a chronic inflammatory disease of the airways (2), the airways being the tubes in the lungs that bring in critical supplies of oxygen from the air into the body. It is included in one of the two major categories lung diseases called obstructive lung diseases, also included is chronic obstructive pulmonary disease usually caused by smoking. These obstructive lung diseases are conditions in which the air can come in, but the exit of air, called expiration, is impaired, in other words obstructed or blocked. The cause of this blockage is usually narrowed airways and increased mucus.

In asthma, a person's lungs react excessively to many triggers (stimuli). Frequently, an asthmatic person is also allergic, and the allergic trigger is the cause of an asthma attack. Other causes of asthma attacks (also called exacerbations) include smoking, environmental pollution, exercise, and upper respiratory infections, such as the common cold or bronchitis. Viral infections are being increasingly recognized as major triggers of asthma attacks. These infections may be found in the future to be even more important than other asthma triggers. Although the attacks can last for only minutes before resolving, sometimes acute asthma exacerbations last for days or weeks. They can even be fatal.

It is becoming more and more clear that asthma and gastroesophageal reflux can often occur in the same person. Gastroesophageal reflux is a condition of irritation and inflammation of the esophagus due to contact of the stomach contents with the lining of the esophagus. Although the cause and effect of how asthma and reflux are related are blurry, in terms of which one triggers the other, when the two conditions (not infrequently) occur in the same person they can trigger each other.

There may be genetic component to asthma, meaning that the built-in messages physically passed on from birth from our parents may play a role. It has long been observed that asthma sometimes "runs in families". Already genes causing susceptibility to asthma in such families are being discovered.

Asthma can occur in pregnancy and requires very close monitoring during that time. Asthma can even begin during pregnancy. Three to five percent of all pregnant women have asthma (11).

The Magnitude of the Problem

Asthma is responsible for:

  • Restricted days - over 100 millions days annually)
  • Huge costs - total annual costs of $6.2 billion
  • Deaths - 5,000 asthma-related deaths in the U.S. each year

The National Asthma Education and Prevention Program (NAEPP) started in 1989 with the goal of raising awareness about the seriousness of asthma as a chronic disease, as well as improving recognition of symptoms of asthma by doctors and the public. The NAEPP is run by the National Heart, Lung, and Blood Institute. Statistics about asthma, including those above, can be obtained from the NAEPP.

Between 12 and 15 million people in the U.S. have asthma (7). One 1998 estimate from the Centers for Disease Control, was even higher at 17 million. In 1998, asthma cost the U.S. $11.3 billion (2).



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