According to new research out of Duke University’s Medical Center, patients who experience gastroesophageal reflux disease (GERD) may be more likely to develop asthma. Findings showed that when tiny amounts of stomach fluid that back up into the esophagus (caused by GERD) are inhaled, it causes changes in the immune system that can increase the development of asthma.

“This is the first experimental evidence in a controlled, laboratory setting linking these two very common conditions in humans,” says senior author Shu Lin MD, PhD, of Duke University. “These data suggest that chronic micro-aspiration of gastric fluid can drive the immune system toward an asthmatic response.”

Since the relationship between GERD and asthma was discovered in the mid-1970s, physicians have been puzzled by the connection. Until this Duke University study was conducted, it was unclear whether GERD caused asthma or if asthma caused GERD.

“This does not mean that everyone with GERD is going to develop asthma, by any means,” says William Parker, assistant professor of surgery at Duke University, co-author of the study. “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.”

The researchers believe that more work should be done to dissect the cellular and molecular mechanisms involved in the relationship between GERD and asthma.