GERD is caused by the weakening of the band of muscle separating the esophagus and the stomach. This band of muscle is called the lower esophageal sphincter (LES). There are a number of risk factors that increase your likelihood of developing GERD. They include obstructive sleep apnea (OSA), obesity, hiatal hernia, pregnancy, smoking, dry mouth, asthma, diabetes, delayed stomach emptying and scleroderma and other connective tissue disorders. 
Effects of long term GERD include esophagitis (irritation and inflammation of the esophagus), Barrett’s esophagus (change in the esophagus cells), strictures (narrowing of the esophagus due to scarring), and esophageal cancer. 
Treatments include antacids and other medications to prevent or block the production of stomach acid and to heal the esophagus. Medications can also be given to strengthen the LES. If medications do not work, surgery is an option. Nissen fundoplication reinforces the LES and Linx strengthens the LES.