The exact cause of Barrett’s esophagus is not yet known. However, the condition is most often seen in people with GERD. GERD occurs when the muscles at the bottom of the esophagus do not work properly. The weakened muscles will not prevent food and acid from coming back up into the esophagus. It’s believed that the cells in the esophagus can become abnormal with long-term exposure to stomach acid. Barrett’s esophagus can develop without GERD, but patients with GERD are 3 to 5 times more likely to develop Barrett’s esophagus. Approximately 5 to 10 percent of people with GERD develop Barrett’s esophagus. It affects men almost twice as often as women and is usually diagnosed after the age of 55. Over time, the cells of the esophageal lining may develop into precancerous cells. These cells may then change into cancerous cells. However, having Barrett’s esophagus doesn’t mean you will get cancer. It’s estimated that only about 0.5 percent of people with Barrett’s esophagus develop cancer.