Backward flow of contents from the stomach into the esophagus causes gastroesophageal reflux or heartburn. The digestive fluid in the stomach irritates the lining of the esophagus, and over a long period of time can cause esophageal damage, including narrowing (stricture) and a condition called Barrett's esophagus (a precancerous change in the cells of the lower esophagus). Lying flat while sleeping may worsen the symptoms. The following conditions increase the risk of this condition: drinking alcohol, obesity, smoking, pregnancy, diabetes, and scleroderma.