Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease that causes scarring in your lungs. IPF is strongly associated with gastroesophageal reflux disease (GERD), a condition where stomach acid flows back into your esophagus. It’s estimated that 90 percent of people with IPF have GERD. GERD is generally considered a risk factor for IPF, but research is ongoing to determine the exact relationship between the two conditions.

Many theories are being investigated to determine whether GERD is a cause of IPF or whether it worsens lung scarring.

It’s thought that GERD may be connected to aspiration of tiny particles of stomach acid into your lungs over time. Some medical researchers think that this microaspiration plays a role in producing scar tissue in your lungs.

Other investigators suggest that this aspiration may be responsible for the acute episodes that occur in IPF. This study also notes that clinical symptoms of reflux are poor predictors of GERD in people with IPF. The authors recommend that doctors carefully investigate and treat for GERD in these people.

Other studies have indicated that abnormal acid gastroesophageal reflux occurred in those with IPF, although they didn’t have the usual GERD symptoms.

There are two lines of thought on this research concerning people with both IPF and GERD: Some researchers think GERD comes first and causes lung fibrosis. Others think IPF comes first and puts pressure on the esophagus, causing GERD. In any case, more research is necessary to find the cause of IPF and develop effective treatments.

No matter what the cause, it’s clear from recent studies that treating people who have IPF for GERD is beneficial.

A 2011 study found that people with IPF who used GERD medication had median survival rates about twice as long as those of patients who didn’t use the medication. Also, there was less lung scarring. The study authors caution that more research is needed, and that it’s possible that GERD may develop as a result of IPF.

A small 2013 study of patients with IPF found that those taking GERD medication had a slower decline in their breathing capability and fewer acute episodes. The authors suggest that GERD is a contributing factor in IPF and that anti-acid therapy may be beneficial.

If you have GERD and you have any symptoms for IPF, such as difficulty breathing and a persistent cough, you should ask your doctor to check for IPF. IPF is very rare and difficult to diagnose. But if it’s caught early, you’ll have a better outcome with the disease.