Gastroesophageal Reflux Disease (GERD) involves the recurrent backflow of the stomach or duodenal contents into the esophagus, leading to troublesome symptoms and potential esophageal mucosal damage. Although GERD is often referred to as a disease, it is more accurately described as a syndrome, as it encompasses a range of symptoms and complications rather than a singular pathological entity, impacting a large number of individuals as the most prevalent upper gastrointestinal problem. Roughly 15 million Americans encounter GERD symptoms.

GERD arises from various causes rather than a single source. The chief factor contributing to GERD is an incompetent lower esophageal sphincter (LES), which generally acts as a barrier against reflux by preventing the backward movement of stomach contents. When the LES fails, gastric contents flow from the stomach into the esophagus, mainly when the individual is lying down or under increased intra-abdominal pressure.

The regurgitation of stomach acid back into the esophagus overwhelms its defensive mechanisms, resulting in esophageal irritation and inflammation, known as esophagitis. The degree of inflammation is influenced by the volume and composition of the refluxed gastric contents, along with the protective capabilities of the esophageal lining.

In a hiatal hernia, a part of the stomach extends into the chest through the esophageal hiatus in the diaphragm. This displacement occurs when the stomach moves upward, breaching the typical abdominal-chest boundary. This anatomical anomaly can exacerbate GERD by compromising the integrity of the LES, which usually prevents stomach acid from entering the esophagus. Stomach acid can freely flow back into the esophagus, causing symptoms like heartburn and regurgitation.

Additional factors, such as delayed gastric emptying causing gastric distension, contribute to post-meal GERD by increasing transient lower esophageal sphincter relaxations. Certain foods and medications can reduce LES pressure, exacerbating GERD symptoms. Obesity poses a risk, as increased intra-abdominal pressure can worsen GERD. Additionally, Tobacco use in general, including smoking and smokeless tobacco products, can worsen GERD symptoms. Smoking specifically has been shown to relax the lower esophageal sphincter (LES), which can allow stomach contents to reflux more easily into the esophagus. Additionally, tobacco use can increase stomach acid production, reduce saliva production (which helps neutralize acid), and impair esophageal motility, all of which can exacerbate GERD symptoms.