The cause of gastroesophageal reflux disease (GERD) is not known. However, having a hiatal hernia may contribute to GERD. A hiatal hernia occurs when the upper part of the stomach pushes above the diaphragm, the muscle that separates the stomach from the chest.

The diaphragm supports the lower esophageal sphincter (LES), the muscles that act as a valve between the esophagus and the stomach. A hiatal hernia makes it easier for stomach acid to back up into the esophagus.

Other factors that may increase the incidence of GERD include:

• Drinking alcohol. Alcohol stimulates acid production and may contribute to a more relaxed LES.
  
  
• Being overweight or obese. Excess weight can increase pressure on the abdominal muscles and the stomach. Some research shows that even moderate weight gain increases a person’s risk of developing GERD
  
  
• Pregnancy. Both the pressure of increased weight and the hormone progesterone, which relaxes muscles, can contribute to reflux in pregnant women.
  
  
• Smoking cigarettes. Smoking reduces the production of saliva, which helps neutralize stomach acid. Coughing provoked by smoking can start episodes of reflux. In addition, the nicotine in cigarettes helps relax the LES.
  
  
• Eating/drinking certain types of foods and beverages. Traditionally, physicians have recommended that patients with GERD avoid certain foods and beverages, including citrus fruits, chocolate, fatty foods, spicy foods, tomato sauce, mint and carbonated and/or caffeinated beverages, which may increase acid production or relax LES muscles. However, recent research questions the necessity of such dietary changes.
  
  
• Eating large meals or lying down soon after eating. Physicians typically recommend that patients eat small meals and avoid lying down for at least three hours after eating. However, there is little evidence to support that reclining after meals can prevent or reduce heartburn associated with GERD, according to recent research.
  
  
• Certain medications – such as sedatives, tranquilizers and calcium channel blockers (medication to treat high blood pressure) – may contribute to reflux. Recent research also indicates that taking a certain type of sleeping pills may also increase the risk of developing nighttime heartburn.
  
  
• Other diseases. GERD occurs more commonly with certain diseases, although the relationship is unclear. Some people with conditions that delay the emptying of the stomach, such as diabetes, experience GERD. People with asthma experience GERD or heartburn frequently, possibly from frequent coughing or the effects of asthma medications. Scleroderma, an autoimmune condition that primarily affects the skin, may also cause esophageal problems that may lead to GERD.