If you have asthma, there is a very good chance you also have GERD. An estimated seven out of 10 people with asthma also suffer from gastroesophageal reflux disease (GERD). Up to 70% of people with asthma have GERD, compared with 20–30% of the general population. These statistics suggest that if you have severe, chronic asthma, which does not respond well to treatment, you are particularly susceptible to GERD.
Researchers have studied the link between GERD and asthma for decades with many concluding the two conditions share common triggers. Asthma is a chronic inflammation of the lung's airway tissues affecting an estimated 20 million Americans according to the National Heart, Lung and Blood Institute.
Asthma attacks are usually triggered by allergens (a substance your body perceives as a threat) as well as bacterial and viral infections. In response, the airways tighten and fill with mucus. This traps air within the lungs and causes the symptoms associated with an attack, such as shortness of breath, tightness in the chest, coughing and wheezing.
Researchers are not sure exactly what the connection is between GERD and asthma, but there are several theories. If you have GERD, you may be breathing the digestive acid from the reflux into your lungs, where the acid irritates the lung's lining and causes spasms in the bronchi, resulting in an asthma attack. It is also possible that when acid enters your esophagus, it dissolves the lining and exposes segments of a major nerve that affects the lungs. This triggers a nerve reflex that makes your airways narrow to prevent acid from entering them, thereby causing shortness of breath.
Another theory suggests that the acid in the esophagus stimulates nerves that connect to nerves in the lungs, which react by narrowing the breathing passages. It appears to be a cycle that spirals from one kind of chronic reaction to another and back again.
You may have both GERD and asthma if you have:
• Increased asthma symptoms after you eat or exercise
• Increased asthma symptoms when you lie down
• Frequent coughing or hoarseness
• Asthma that doesn’t respond to the standard asthma treatments.
GERD may alter the immune system and raise the risk of asthma, according to a new study that helps explain why so many people with asthma also suffer from gastroesophageal reflux disease.
The study shows that inhaling small amounts of stomach acid back up into the esophagus and lungs, a hallmark of GERD, slowly produces changes in the immune system that may lead to the development of asthma.
"This does not mean that everyone with GERD is going to develop asthma, by any means," says researcher William Parker, assistant professor of surgery at Duke University Medical Center, "But it may mean that people with GERD may be more likely to develop asthma. If there is an upside to this, it is that developing GERD is something we can pretty much treat and control."
In the study, published in the European Journal of Clinical Investigation, researchers mimicked the effects of GERD in laboratory mice by inserting small amounts of gastric fluid into their lungs for eight weeks. They then compared how the immune systems of these mice responded to exposure to allergens, a key factor in the development of asthma, to the immune response of normal, healthy mice.
The results showed that the GERD mice responded very differently to allergens. Specifically, they developed an immune response similar to that found in people with asthma by releasing a specific type of infection-fighting T-cell. Healthy mice responded in a more balanced manner releasing two types of immune cells.
Researchers say rising rates of reflux and GERD may be driving increasing rates of asthma, but many of the risk factors behind this phenomenon may be modifiable.
"People should avoid the risk factors for GERD. We strongly believe that the rise in asthma, particularly among adults in the country, is in large measure due to lifestyle choices that can be changed," Parker says.
Other studies have found links between GERD and other pulmonary disorders, such as sinusitis and chronic obstructive pulmonary disease (COPD).
See videos about the acid reflux and asthma connection.
GERD and Asthma - References
By Mortin - Copyright 2010
Last modification 05/02/2010