Studies have shown that anywhere between 50 and 90 percent of patients with asthma experience some aspect of gastroesophageal reflux disease (GERD). But does GERD cause asthma or does asthma cause GERD? Researchers at Duke University Medical Center appear to have found support for the first scenario - that GERD may drive the development of asthma.
Working with laboratory mice, Dr. Shu Lin, an assistant professor of surgery and immunology at Duke, discovered that when mice inhaled tiny amounts of stomach fluid, then changes were made in the mice's immune systems that appear to be associated with asthma.
In the experiments, researchers inserted miniscule amounts of gastric fluid into the lungs of the mice (mimicking GERD) over a period of eight weeks. They then compared these animals' immune systems with those of mice who were not exposed to gastric fluid. The mice who had the gastric fluid in their lungs developed a type of immune system reaction characteristic of asthma.
At the study's conclusion, the researchers made clear that these results do not mean that everyone with GERD is going to develop asthma. However, it does provide support for the fact that people with GERD may be more likely to develop asthma than those individuals without GERD. For me, this study is a stark reminder of the importance of working with an astute physician if someone in your family is displaying symptoms of GERD. While this study was based mice and not humans, it is still important to remember that it only took eight weeks of untreated acid reflux for the mice to undergo important changes in their immune system which left them more susceptible to asthma.