Gastroesophageal reflux disease, also known as GERD or heart burn, is a chronic disease in which stomach acids flow backwards into the esophagus. GERD can cause damage to the lungs, or give rise to ulcers in the esophagus, if it not treated properly.  Asthma on the other hand, is a chronic disease that is characterized by breathing disorders caused by the overreaction of airways to certain irritants or allergens. Although no exact connection has been established between the two, studies have shown that they can, in fact, have some affect on one another.

According to a new study, GERD can slowly cause changes in the immune system of the body, thus triggering asthma. Doctors most often look at GERD as the cause of asthma when asthma begins in adult-hood, when asthma symptoms becomes worse after eating, exercising or lying down, or when asthma does not react to standard treatments.

One theory behind GERD leading to asthma is characterized by the acid flow that can cause permanent damage to the linings of the lungs, throat and airways, trigging persistent cough and making breathing difficult. Another hypothesis is that inhaling small amounts of stomach acid back into the lungs and the esophagus can decrease airflow into the lungs by narrowing the airways. Both of which can trigger asthma.

However, despite a number of studies on this topic, the relationship has still not been verified, and remains unclear.