Barrett's Esophagus in an Area with an Exceptionally Low Prevalence of Helicobacter pylori Infection

The global prevalence of Barrett's esophagus: A systematic review of the published literature

BACKGROUND

Determining the prevalence of Barrett's esophagus is important for defining screening strategies. We aimed to synthesize the available data, determine Barrett's esophagus prevalence, and assess variability.

METHODS

Three databases were searched. Subgroup, sensitivity, and meta-regression analyses were conducted and pooled prevalence was computed.

RESULTS

Of 3510 studies, 103 were included. In the general population, we estimated a prevalence for endoscopic suspicion of Barrett's esophagus of (a) any length with histologic confirmation of intestinal metaplasia as 0.96% (95% confidence interval: 0.85-1.07), (b) ≥1 cm of length with histologic confirmation of intestinal metaplasia as 0.96% (95% confidence interval: 0.75-1.18) and (c) for any length with histologic confirmation of columnar metaplasia as 3.89% (95% confidence interval: 2.25-5.54) . By excluding studies with high-risk of bias, the prevalence decreased to: (a) 0.70% (95% confidence interval: 0.61-0.79) and (b) 0.82% (95% confidence interval: 0.63-1.01). In gastroesophageal reflux disease patients, we estimated the prevalence with afore-mentioned criteria to be: (a) 7.21% (95% confidence interval: 5.61-8.81) (b) 6.72% (95% confidence interval: 3.61-9.83) and (c) 7.80% (95% confidence interval: 4.26-11.34). The Barrett's esophagus prevalence was significantly influenced by time period, region, Barrett's esophagus definition, Seattle protocol, and study design. There was a significant gradient East-West and North-South. There were minimal to no data available for several countries. Moreover, there was significant heterogeneity between studies.

CONCLUSION

There is a need to reassess the true prevalence of Barrett's esophagus using the current guidelines in most regions. Having knowledge about the precise Barrett's esophagus prevalence, diverse attitudes from educational to screening programs could be taken.

Systematic review and meta-analysis of prevalence and risk factors for Barrett's esophagus

BACKGROUND AND AIMS

Although screening for Barrett's esophagus (BE) is recommended in individuals with multiple risk factors, the type and number of risk factors necessary to trigger screening is unclear. In this systematic review and meta-analysis, we aimed to assess the relationship between number of risk factors and prevalence of BE.

METHODS

Through October 17, 2018 we searched studies that described the prevalence of BE in the general population and based on presence of risk factors that included GERD, male gender, age >50 years, family history of BE and esophageal adenocarcinoma, and obesity (defined as body mass index >35). Risk of BE based on number of risk factors was assessed using meta-regression while controlling for potential confounders.

RESULTS

Of 2741 studies, 49 were included in the analysis (307,273 individuals, 1948 with biopsy specimen-proven BE). Indications varied by study. The prevalence of BE for various populations was as follows: low-risk general population, .8% (95% confidence interval [CI], .6%-1.1%); GERD, 3% (95% CI, 2.3%-4%); GERD plus presence of any other risk factor, 12.2% (95% CI, 10.2%-14.6%); family history, 23.4% (95% CI, 13.7% -37.2%); age >50, 6.1% (95% CI, 4.6%-8.1%); obesity, 1.9% (95% CI, 1.2%-3%); and male sex, 6.8% (95% CI, 5.3%-8.6%). Prevalence of BE varied significantly between Western and non-Western populations. In a meta-regression, controlling for the region of the study, age, and gender, there was a positive linear relationship between the number of risk factors and the prevalence of BE.

CONCLUSIONS

Results of this study provide estimates of BE prevalence based on the presence and the number of risk factors. These results add credence to current guidelines that suggest screening in the presence of multiple risk factors.

Prevalence of Barrett's Esophagus in Asian Countries: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The prevalence and risk factors of Barrett's esophagus (BE) in Asian countries are unclear. Studies report a wide range of BE prevalence in Asian countries. We conducted a systematic review and meta-analysis to examine the prevalence of BE and its temporal changes and risk factors in Asian countries.

METHODS

Two investigators performed independent literature searches by using PubMed and EMBASE databases, and subsequent data abstraction for studies had to meet several set inclusion and exclusion criteria. Pooled BE prevalence was calculated by using a random-effect model. Estimates of relative risk for possible risk or protective factors were also calculated.

RESULTS

A total of 51 studies (N = 453,147), mainly from Eastern Asia, were included. The pooled prevalence of endoscopic BE was 7.8% (95% confidence interval, 5.0-12.1; 23 studies) and of histologically confirmed BE was 1.3% (95% confidence interval, 0.7-2.2; 28 studies). Most of histologic BE (82.1%) was short-segment BE (<3 cm). There was a trend toward an increase in prevalence of BE over time from 1991 to 2014, especially in Eastern Asian countries. Within BE cohorts, pooled prevalence of low-grade dysplasia, high-grade dysplasia, and esophageal adenocarcinoma was 6.9%, 3.0%, and 2.0%, respectively. Reflux symptoms, male sex, hiatus hernia, and smoking were associated with a significantly increased risk of histologic BE in patients with BE compared with patients without BE. However, half of the patients with histologic BE did not have reflux symptoms.

CONCLUSIONS

BE is not uncommon in Asian countries and seems to share similar risk factors and potential for neoplastic progression to those seen in Western countries.

Helicobacter pylori infection--a boon or a bane: lessons from studies in a low-prevalence population

Helicobacter pylori (H. pylori) infection is etiologically associated with gastric cancer and peptic ulcer diseases which are both important public health burdens which could be largely eliminated by H. pylori eradication. However, some investigators urge caution based on the hypothesis that eradication of H. pylori may result in an increase in the incidence of gastroesophageal reflux disease, esophageal adenocarcinoma, and childhood asthma. The ethnic Malays of northeastern Peninsular Malaysia have long had a low prevalence of H. pylori infection and, as expected, the incidence of gastric cancer and its precursor lesions is exceptionally low. The availability of a population with a low H. pylori prevalence and generally poor sanitation allows separation of H. pylori from the hygiene hypothesis and direct testing of whether absence of H. pylori is associated with untoward consequence. Contrary to predictions, in Malays, erosive esophagitis, Barrett's esophagus, distal esophageal cancers, and childhood asthma are all of low incidence. This suggests that H. pylori is not protective rather the presence of H. pylori infection is likely a surrogate for poor hygiene and not an important source of antigens involved in the hygiene hypothesis. Helicobacter pylori in Malays is related to transmission from H. pylori-infected non-Malay immigrants. The factors responsible for low H. pylori acquisition, transmission, and burden of H. pylori infection in Malays remain unclear and likely involves a combination of environmental, host (gene polymorphisms), and strain virulence factors. Based on evidence from this population, absence of H. pylori infection is more likely to be boon than a bane.

What indigestion means to the malays?

Despite being a large ethnic group within the South-East Asia, there is a paucity of reported literatures on dyspepsia in the Malay population. Recent population-based studies indicate that uninvestigated dyspepsia, based on the Rome II criteria, is reported in 12.8% and 11.6% of Malays in the urban and rural communities respectively. Organic causes of dyspepsia including upper gastrointestinal tract cancers, its precancerous lesions, and erosive diseases are uncommon which is largely due to an exceptionally low prevalence of Helicobacter pylori infection in this population. On the other hand, functional dyspepsia and irritable bowel syndrome are relatively common in the Malays than expected. Within a primary care setting, functional dyspepsia, based on the Rome III criteria, is reported in 11.9% of Malays, of which epigastric pain syndrome is found to be more common. Married Malay females are more likely to have functional dyspepsia and psychosocial alarm symptoms. Also based on the Rome III criteria, irritable bowel syndrome, commonly overlapped with functional dyspepsia, is reported in 10.9% of Malays within a community-based setting. Rather than psychosocial symptoms, red flags are most likely to be reported among the Malays with irritable bowel syndrome despite having a low yield for organic diseases. Based upon the above observations, "proton pump inhibitor test" is probably preferable than the "test and treat H. pylori" strategy in the initial management of dyspepsia among the Malays.

A Rome III survey of functional dyspepsia among the ethnic Malays in a primary care setting

Backgrounds

The study aimed to survey for FD in a primary care setting in a population known to have an extremely low prevalence of Helicobacter pylori (H. pylori) infection, with the hypothesis that in such a population, dyspepsia should have been relatively less common.

Methods

The Rome III FD Diagnostic Questionnaire was translated into the Malay language and later tested for reliability. A prospective cross-sectional survey was then performed involving 160 Malay patients attending primary care clinic after informed consent. Patients positive for symptoms of FD were subjected to upper endoscopy and exclusion of H. pylori infection. Univariable and multivariable analyses were used to test for associated risk factors.

Results

The back-translated questionnaire was similar to the original English version and was reliable (Cronbach Alpha-coefficient 0.85). Of the 160 surveyed subjects, 19 of them (11.9%) had symptoms of FD. With exclusion of erosive diseases (3/160 or 1.9%) from endoscopy, 16 subjects or 10% had FD. None of the 19 subjects were positive for H. pylori infection. Epigastric pain syndrome was present in 11/16 (68.8%) and the rest, overlap with postprandial distress syndrome. With multivariable analysis, a married status (OR = 8.1; 95% CI 1.0-36.5) and positive psychosocial alarm symptoms (OR = 3.8; 95% CI 1.0-14.0) were associated with FD. Of those married subjects, females were more likely to have FD and psychosocial symptoms than men (6.3% vs. 1.9%), P = 0.04.

Conclusions

FD was more common than one had expected among Malays attending primary care clinic in an area with low prevalence of H. pylori.

Towards understanding the low prevalence of Helicobacter pylori in Malays: genetic variants among Helicobacter pylori-negative ethnic Malays in the north-eastern region of Peninsular Malaysia and Han Chinese and South Indians

OBJECTIVES

To identify gene polymorphisms that differ between Malays, Han Chinese and South Indians, and to identify candidate genes for the investigation of their role in protecting Malays from Helicobacter pylori (H. pylori) infection.

METHODS

Malay participants born and residing in Kelantan with a documented absence of H. pylori infection were studied. Venous blood was used for genotyping using the Affymetrix 50K Xba I kit. CEL files from 141 Han Chinese and 76 South Indians were analyzed to compare their allele frequency with that of the Malays using fixation index (FST ) calculation. The single nucleotide polymorphisms (SNPs) with the highest allele frequency (outliers) were then examined for their functional characteristics using F-SNP software and the Entrez Gene database.

RESULTS

In all, 37 Malays were enrolled in the study; of whom 7 were excluded for low genotyping call rates. The average FST estimated from the genome-wide data were 0.038 (Malays in Kelantan vs the South Indians), 0.015 (Malays in Kelantan vs Han Chinese) and 0.066 (Han Chinese vs South Indians), respectively. The outlier gene variants present in Malays with functional characteristics were C7orf10 (FST  0.29988), TSTD2 (FST  0.43278), SMG7 (FST  0.29877) and XPA (FST  0.43393 and 0.43644).

CONCLUSION

Genetic variants possibly related to protection against H. pylori infection in ethnic Malays from the north-eastern region of Peninsular Malaysia were identified for testing in subsequent trials among infected and uninfected Malays.