What Causes Barrett's Esophagus?

Barrett’s esophagus (BE) is an abnormal metaplastic change in the esophageal epithelium (similar to intestinal tissue). BE may progress into esophageal adenocarcinoma, which is a rare cancer type.

Even though the risk of converting BE to cancer is low, periodic checkups for precancerous cells or dysplasia must be performed.

Usually, BE does not have any symptoms, but when associated with gastroesophageal reflux disease (GERD), it exhibits symptoms that include repeated heartburn, trouble swallowing, bloody vomit, and tarry stools.

Causes

The specific cause of BE is not exactly known, but one of the major risk factors is gastroesophageal reflux disease (GERD). People with long-term GERD are at higher risk of BE. In GERD, the sphincter valve at the lower end of the esophagus is damaged and allows the back flow of acids from the stomach into the esophagus.

Patients with GERD are found to have metaplasia in the cells lining the wall of the esophagus because of the acid. This consequently leads to BE.

Ten to twenty percent of patients with GERD present with BE. It is also possible for the people without GERD to develop BE. But the condition with GERD occurrs 3 to 5 times more often in people with GERD than people without GERD.

The other risk factor for BE is hiatal hernia in which an acidic sack-like muscle from the stomach protrudes through diaphragm into the esophagus and thereby decreases the peristalsis. This in turn can cause BE. In studies, patients affected with GERD who progressed to BE were diagnosed with hiatal hernia.

Other Risk Factors

Age, Sex, and Race

The risk factors for BE are dependent age, sex, and race, as well as few other factors like tobacco smoking, and heartburn symptoms that last longer than ten years. P eople aged 60 years and above are most often diagnosed with BE. There is often a delay of 10 to 20 years before BE is diagnosed. . When compared with women, men tend to have three to four times the chance of developing BE. In addition, BE is more prevalent among c aucasian people.

Obesity

A nother risk factor for BE is obesity. A case-control study was conducted by comparing patients affected with and without BE. That study demonstrated that there is a direct relationship between high body mass index (BMI) and BE. A meta-analysis also concluded that people with a BMI higher than 30 kg/m2 are at greater risk of BE than the people with a BMI lower than 30 kg/m2.

In another case-control study by Edelstein and colleagues, it was reported that the total risk for BE was greater in people with higher waist and hip ratios.

Alcohol

Alcohol consumption has also been considered as a risk factor for BE. Studies have shown an association between alcohol consumption and BE. BE occurs more commonly in people consuming alcohol at the highest level than people at a lower level.

Diabetes and Metabolic Syndrome

Type 2 diabetes increases risk for BE by 49% , while metabolic syndrome carries a 2-fold increase in risk in people with or without the symptoms of acid reflux. S tudies indicate that the increased risk of BE from both of these factors (diabetes and metabolic syndrome) is independent of other risk factors such as BMI, alcohol consumption, and smoking.

Absence of Heliobacter pylori Infection

Infection by Heliobacter pylori (H. pylori) causes gastritis, stomach ulcers, and gastric cancers. However, it was found that BE and bacterial infection are inversely related when endoscopically comparing people with and without BE. The bacterium has a strong relationship with abnormal change in the cells of the intestine and the stomach. The bacterial infection prevents BE by reducing the secretion of gastric acid. A  study on H. pylori found that infection with a cytotoxin-associated gene A (cagA+) strain shields against BE. Another study from Japan also indicates that people with BE have a lower prevalence of Helicobacter infection. Therefore, absence of H. pylori infection can increase the risk of BE.

The other risk factors for BE are lower birth weight, obstructive sleep apnea (OSA), and increased adipokine and cytokine levels. People who were born less at than 32 weeks of gestation are more likely to develop BE. OSA associated with a proinflammatory condition may lead to BE. Furthermore, the levels of cytokines and adipokines produced by adipose tissue were high in patients affected with BE.