Acid reflux is the reflux of stomach acid into the esophagus Common causes of gastroesophageal reflux disease and pathogenic mechanisms Gastroesophageal reflux disease refers to heartburn, reflux and other symptoms and/or esophagitis caused by gastroesophageal reflux, including reflux esophagitis (RE) and non-erosive reflux disease (NERD) Incidence The incidence of RE in Beijing and Shanghai is 1.7%. With reflux symptoms is 8.97%. Etiology and pathogenic mechanism I. Reduced anti-reflux function of the esophagus 1. Lower esophageal sphincter relaxation Patients have frequent transient lower esophageal sphincter relaxation, and patients mostly have acid reflux. Gastric dilatation and increased intra-abdominal pressure can induce relaxation through the vagal reflex. The lower esophageal sphincter pressure decreases. In normal people, the lower esophageal sphincter remains contracted in tension at rest, and if the pressure decreases (less than 6 mmHG), it causes reflux of food from the stomach into the esophagus. Factors that cause its pressure to decrease include: high fat, chocolate, coffee, etc., calcium antagonists, diazepam, theophylline, etc., cholecystokinin, pancreatic fluid, pancreatic hyperglycemia, etc. 3, structural abnormalities at the gastroesophageal junction such as esophageal hiatal hernia II, esophageal clearance capacity is reduced esophageal clearance capacity includes propulsive peristalsis, salivary neutralization and gravity of the food mass. Among them, propulsive peristalsis is the most important, and when the peristaltic strength is reduced by 30 mmHg or less, the refluxed material cannot be emptied. Third, the esophageal mucosal defense is weakened, including pre-epithelial factors, epithelial factors, and post-epithelial factors. When the mucosal defense barrier is damaged, even normal reflux can lead to RE. Patients mostly have esophageal allergy, especially acid allergy, and most of them can recover after antacid treatment. V. Delayed gastric emptying VI. Other factors Infants, pregnancy, obesity, scleroderma, diabetes mellitus. High gastric acid secretion state.