Abnormalities in the body such as hiatal hernias may also cause GERD. Hiatal hernias occur when the upper part of the stomach moves up into the chest. The stomach can slip through an opening found in the diaphragm. The diaphragm is the muscle wall that separates the stomach from the chest. Hiatal hernias may cause GERD because of stomach acid flowing back up through the opening; however, most produce no symptoms.

Other factors that can contribute to GERD include

• obesity
• pregnancy
• certain medications, such as asthma medications, calcium channel blockers, and many antihistamines, pain killers, sedatives, and antidepressants
• smoking, or inhaling secondhand smoke

People of all ages can develop GERD, some for unknown reasons.