The association between Barrett's esophagus and Helicobacter pylori infection: a meta-analysis

Helicobacter pylori: the balance between a role as colonizer and pathogen

The isolation of Helicobacter pylori from the human stomach produced significant changes in how gastroenterologists, immunologists, epidemiologists, pathologists and microbiologists have approached gastro-duodenal diseases in the last half of the XX century. However, research of this organism has progressed greatly in the first decade of this century, evidence suggest that H. pylori is associated with disease only in humans older than 40 years, while, the lack of H. pylori colonization is associated with the emergence of new diseases, particularly in younger individuals. These differing effects of H. pylori colonization have created two contrasting concepts: the 'bad' and the 'good' Helicobacter. Following from renewed interest in the normal human microbiome, we need to reconsider our definitions and perhaps recognize that H. pylori might be a normal member of the human gastric microbiome in ancient humans that gradually, as results of the improvement in our environment, is disappearing.

Barrett’s oesophagus: Evidence from the current meta-analyses

Guidelines have been published regarding the management of Barrett’s oesophagus (columnar-lined oesophagus). These have examined the role of surveillance in an effort to detect dysplasia and early cancer. The guidelines have provided criteria for enrolment into surveillance and some risk stratification with regard to surveillance interval. The research basis for the decisions reached with regard to cancer risk is weak and this manuscript has examined the available data published from meta-analyses up to 25^th April 2013 (much of which has been published since the guidelines and their most recent updates have been written). There were 9 meta-analyses comparing patients with Barrett’s oesophagus to control populations. These have demonstrated that Barrett’s oesophagus is more common in males than females, in subjects who have ever smoked, in subjects with obesity, in subjects with prolonged symptoms of gastro-oesophageal reflux disease, in subjects who do not have infection with Helicobacter pylori and in subjects with hiatus hernia. These findings should inform public health measures in reducing the risk of Barrett’s oesophagus and subsequent surveillance burden and cancer risk. There were 8 meta-analyses comparing different groups of patients with Barrett’s oesophagus with regard to cancer risk. These have demonstrated that there was no statistically significant benefit of antireflux surgery over medical therapy, that endoscopic ablative therapy was effective in reducing cancer risk that there was similar cancer risk in patients with Barrett’s oesophagus independent of geographic origin, that the adenocarcinoma incidence in males is twice the rate in females, that the cancer risk in long segment disease showed a trend to be higher than in short segment disease, that there was a trend for higher cancer risk in low-grade dysplasia over non-dysplastic Barrett’s oesophagus, that there is a lower risk in patients with Helicobacter pylori infection and that there is a significant protective effect of aspirin and statins. There were no meta-analyses examining the role of intestinal metaplasia. These results demonstrate that guidance regarding surveillance based on the presence of intestinal metaplasia, segment length and the presence of low-grade dysplasia has a weak basis, and further consideration should be given to gender and helicobacter status, ablation of the metaplastic segment as well as the chemoprotective role of aspirin and statins.

Helicobacter pylori and gastroesophageal reflux disease

PURPOSE OF REVIEW

The purpose of the review is to discuss key studies conducted on the intriguing relationship between Helicobacter pylori and gastroesophageal reflux disease.

RECENT FINDINGS

Epidemiological studies have repeatedly described a negative association between H. pylori infection and erosive esophagitis, Barrett's esophagus, and esophageal adenocarcinoma, but not between H. pylori and gastroesophageal reflux disease symptoms. Especially, infection with CagA-positive strains appears to protect the distal esophagus by causing fundic gland atrophy and impaired gastric acid secretion. Although earlier reports suggested the development of erosive esophagitis after H. pylori eradication, more recent studies discuss that H. pylori eradication usually does not have an important clinical impact on gastroesophageal reflux disease.

SUMMARY

Gastric atrophy is the most widely accepted mechanism by which the distal esophagus is protected from abnormal acid exposure in patients with H. pylori infection. The clinical impact of H. pylori infection on the prevalence of erosive esophagitis and Barrett's esophagus remains a matter of debate. In areas with a high prevalence of H. pylori-induced atrophic gastritis, the protection that this infection may afford against gastroesophageal reflux disease is not comparable to the risk that H. pylori poses for the development of gastric cancer.

Symptomatic reflux disease: the present, the past and the future

The worldwide incidence of GORD and its complications is increasing along with the exponentially increasing problem of obesity. Of particular concern is the relationship between central adiposity and GORD complications, including oesophageal adenocarcinoma. Driven by progressive insight into the epidemiology and pathophysiology of GORD, the earlier belief that increased gastroesophageal reflux mainly results from one dominant mechanism has been replaced by acceptance that GORD is multifactorial. Instigating factors, such as obesity, age, genetics, pregnancy and trauma may all contribute to mechanical impairment of the oesophagogastric junction resulting in pathological reflux and accompanying syndromes. Progression of the disease by exacerbating and perpetuating factors such as obesity, neuromuscular dysfunction and oesophageal fibrosis ultimately lead to development of an overt hiatal hernia. The latter is now accepted as a central player, impacting on most mechanisms underlying gastroesophageal reflux (low sphincter pressure, transient lower oesophageal sphincter relaxation, oesophageal clearance and acid pocket position), explaining its association with more severe disease and mucosal damage. Since the introduction of proton pump inhibitors (PPI), clinical management of GORD has markedly changed, shifting the therapeutic challenge from mucosal healing to reduction of PPI-resistant symptoms. In parallel, it became clear that reflux symptoms may result from weakly acidic or non-acid reflux, insight that has triggered the search for new compounds or minimally invasive procedures to reduce all types of reflux. In summary, our view on GORD has evolved enormously compared to that of the past, and without doubt will impact on how to deal with GORD in the future.

Association between Helicobacter pylori and Barrett's esophagus: a case-control study

OBJECTIVES

The estimated association between Helicobacter pylori and Barrett's esophagus (BE) has been heterogenous across previous studies. In this study, we aimed to examine the association between H. pylori and BE and to identify factors that may explain or modify this association.

METHODS

We conducted a case-control study in which we used screening colonoscopy controls recruited from primary care clinics as our primary control group in order to minimize selection bias. All participants underwent an esophagogastroduodenoscopy with gastric mapping biopsies. We used logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs) to estimate the association between H. pylori and BE while controlling for confounders.

RESULTS

We identified 218 cases and 439 controls. The overall OR for the association between H. pylori and BE after controlling for age and white race was 0.55 (95% CI: 0.35-0.84). We observed an even stronger inverse association (OR: 0.28; 95% CI: 0.15, 0.50) among participants with corpus atrophy or antisecretory drug use ≥ 1 time per week (factors thought to lower gastric acidity), and no inverse association in patients without these factors (OR: 1.32; 95% CI: 0.66, 2.63).

CONCLUSIONS

The association between H. pylori and a decreased risk for BE appears to occur in patients with factors that would likely lower gastric acidity (corpus atrophy or taking antisecretory drugs at least once a week).

Association between Helicobacter pylori and Barrett's esophagus, erosive esophagitis, and gastroesophageal reflux symptoms

BACKGROUND & AIMS

Infection with Helicobacter pylori, particularly the cytotoxin-associated gene A (cagA)+ strain, is believed to protect against Barrett's esophagus, but it is not clear if it protects against gastroesophageal reflux disease (GERD). We aimed to determine whether H pylori infection is associated with GERD symptoms, erosive esophagitis, and Barrett's esophagus within the same cohort.

METHODS

We analyzed data from a case-control study of 533 men (ages, 50-79 y) who underwent colorectal cancer screening at 2 tertiary medical centers in Michigan between 2008 and 2011 and who also were recruited to undergo upper endoscopy. We assessed 80 additional men found to have Barrett's esophagus during clinically indicated upper-endoscopy examinations. Logistic regression was used to estimate the associations between serum antibodies against H pylori or cagA and GERD symptoms, esophagitis, and Barrett's esophagus, compared with randomly selected men undergoing colorectal cancer screens (n = 177).

RESULTS

H pylori infection was associated inversely with Barrett's esophagus (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.29-0.97), particularly the cagA+ strain (OR, 0.36; 95% CI, 0.14-0.90). There was a trend toward an inverse association with erosive esophagitis (H pylori OR, 0.63; 95% CI, 0.37-1.08; and cagA+ OR, 0.47; 95% CI, 0.21-1.03). However, GERD symptoms were not associated with H pylori infection (OR, 0.948; 95% CI, 0.548-1.64; and cagA+ OR, 0.967; 95% CI, 0.461-2.03).

CONCLUSIONS

Based on a case-control study, infection with H pylori, particularly the cagA+ strain, is associated inversely with Barrett's esophagus. We observed a trend toward an inverse association with esophagitis, but not with GERD symptoms.

Carcinogenesis of Barrett's esophagus: a review of the clinical literature

Barrett's esophagus (BE) is a premalignant condition of esophageal adenocarcinoma (EAC). Although the incidence of BE has risen rapidly in the West, it is rare in Asia despite a recent increase in the prevalence of gastroesophageal reflux disease. Controversies over the definition of BE are presented because most cases show short-segment BE, especially ultra-short BE, in Asia. Here we review possible risk factors for the development of EAC, particularly possible roles of ethnicity, specialized intestinal metaplasia (SIM), BE length, and environmental factors, such as Helicobacter pylori infection and obesity. Additionally, we summarize recent studies on the effect of chemoprevention including proton pump inhibitors, nonsteroidal anti-inflammatory drugs or aspirin in order to reduce the risk of neoplastic progression in BE patients. Although substantial knowledge of risk factors of dysplasia/EAC in BE is shown, the risk for neoplastic development may be influenced by geographic variation, study population, the presence or absence of SIM or dysplasia at baseline, and the small number of BE patients investigated. Recently, the efficiency of surveillance for BE patients has been discussed from the standpoint of cost-effectiveness. It may be too difficult to draw conclusions because no randomized clinical trials of BE surveillance have been performed.

Cigarette smoking and the risk of Barrett's esophagus: a systematic review and meta-analysis

BACKGROUND AND AIM

Barrett's esophagus (BE) is a premalignant condition to esophageal adenocarcinoma. It is currently not clear whether cigarette smoking increases the risk of developing BE, and no meta-analysis has been performed on the topic. We conducted a systematic review and meta-analysis, providing a quantitative estimate of the increased risk of BE associated with cigarette smoking, to help clarify whether a relationship exists between smoking and BE.

METHODS

Four electronic databases (Medline, PubMed, Embase, and Current Contents Connect) were searched to May 17, 2013, for observational studies of BE patients. We calculated pooled odds ratios (ORs) and 95% confidence intervals (CIs) using a random effects model for the association of smoking with BE. BE patients were compared with non-gastroesophageal reflux disease (GERD) controls as well as with population-based and GERD controls.

RESULTS

Thirty-nine studies comprising 7069 BE patients were included in the meta-analysis. Having ever-smoked was associated with an increased risk of BE compared with non-GERD controls (OR 1.44; 95% CI 1.20-1.74), population-based controls (OR 1.42; 95% CI 1.15-1.76), but not GERD controls (OR 1.18; 95% CI 0.75-1.86). The meta-analyses of the studies reporting the lowest and highest number of pack-years smoked showed an increased risk of BE (OR 1.41; 95% CI 1.22-1.63) and (OR 1.53; 95% CI 1.27-1.84), respectively.

CONCLUSION

Cigarette smoking was associated with an increased risk of BE. Being an ever-smoker was associated with an increased risk of BE in all control groups. A greater number of pack-years smoked was associated with a greater risk of BE.

The prevalence of Helicobacter pylori infection in the Netherlands

BACKGROUNDS

The prevalence of Helicobacter pylori has been declining in the developed countries, as it has the incidence of distal gastric carcinoma. Monitoring this decline and identifying populations not benefiting from this decline is a fit task for public health authorities, with blood donors an obvious source of sera.

MATERIALS AND METHODS

We tested 1550 randomly selected blood donors, spread over 5-10 year age cohorts, from four regions in the southern half of The Netherlands, for the presence of antibodies against H. pylori and the CagA antigen. These donors were drawn from an area comprising 46% of the native Dutch population, but did not include non-European immigrants.

RESULTS

We observed an age specific decline in the mean seroprevalence of H. pylori from 48% for donors born between 1946 and 1935 to 16% for those born between 1987 and 1977. In H. pylori positive donors, the CagA seroprevalence declined from 38% to 14% in the same age cohorts. There were no significant differences between regions in either prevalence.

CONCLUSIONS

Our results are compatible with a persistent age-cohort phenomenon for H. pylori prevalence, with the most pronounced decline of CagA+ strains. Nevertheless, almost one in six of the young native Dutch population remains H. pylori positive, implying that, without specific intervention, this bacterium will remain common over the coming decades.

Evaluation of anatomical and functional changes esophageal stump of patients with advanced megaesophagus submitted to subtotal laparoscopic esophagectomy

PURPOSE

Evaluate anatomical and functional changes of the esophageal stump and gastric fundus of patients with advanced megaesophagus, submitted to laparoscopic subtotal esophagectomy.

METHODS

Twenty patients with advanced megaesophagus, previously submitted to a videolaparoscopic subtotal esophagectomy, were evaluated. Were conducted: radiological evaluation of the stump esophagus with transposed stomach, electromanometric, endoscopic examination and histopathology of the esophageal stump and gastric fundus, without making gastric tube or pyloroplasty.

RESULTS

It was observed that the average height and pressure of the anastomosis, in the electromanometric evaluation, were 23.45cm (±1.84cm) and 7.55mmHg (±5.65mmHg). In patients with megaesophagus III, the pressure of the anastomosis was 10.91mmHg (±6.33mmHg), and pressure from the UES, 31.89mmHg (±14.64mm Hg), were significantly higher than those in grade IV. The pathological evaluation detected mild esophagitis in 35% of patients, moderate in 20% and acanthosis glicogenica in 45%. The examination of the gastric fundus showed that 50% of patients were infected with Helicobacter pylori. Chronic gastritis occurred in 95% of the patients.

CONCLUSIONS

The laparoscopic esophagectomy shown to be effective in the treatment of advanced achalasia. The cervical level anastomosis protects the esophageal stump from the aggression resulted from gastric reflux after the esophagectomy.

Polymorphism in the Helicobacter pylori CagA and VacA toxins and disease

Half of the world's population is infected with Helicobacter pylori and approximately 20% of infected individuals develop overt clinical disease such as ulcers and stomach cancer. Paradoxically, despite its classification as a class I carcinogen, H. pylori has been shown to be protective against development of asthma, allergy, and esophageal disease. Given these conflicting roles for H. pylori, researchers are attempting to define the environmental, host, and pathogen interactions that ultimately result in severe disease in some individuals. From the bacterial perspective, the toxins, CagA and VacA, have each been shown to be polymorphic and to contribute to disease in an allele-dependent manner. Based on the notable advances that have recently been made in the CagA field, herein we review recent studies that have begun to shed light on the role of CagA polymorphism in H. pylori disease. Moreover, we discuss the potential interaction of CagA and VacA as a mediator of gastric disease.