Epidemiology and diagnosis of Helicobacter pylori infection

Epidemiology, Diagnosis, and Risk Factors of Helicobacter pylori Infection in Children

H. pylori infection is a global public health problem associated with some gastrointestinal diseases in children, especially in developing countries, since prevalence of H. pylori is low in the developed world. Both noninvasive (stool antigen test, urea breath test, and blood test) and invasive (histology, rapid urease test, and microbiological culture) tests have been utilized to detect H. pylori infection. However, a single test is not reliable enough and does not provide accurate enough data to determine H. pylori infection among children. Risk factors of H. pylori infection in children were related to ethnicities, household properties, geographic location, living conditions, water sources, type of housing, presence/absence of sewage systems, and garbage collection within the living environment. These risk factors were usually associated with the socioeconomic status of the family. This review article aims to determine the gaps in the knowledge of the epidemiology, risk factors, and diagnostic tests of H. pylori infection among children.

How to cite this article: Ozbey G, Hanafiah A. Epidemiology, Diagnosis, and Risk Factors of Helicobacter pylori Infection in Children. Euroasian J Hepato-Gastroenterol 2017;7(1):34-39.

Investigation of Helicobacter pylori infection among symptomatic children in Hangzhou from 2007 to 2014: a retrospective study with 12,796 cases

Background and Aim

The infection of Helicobacter pylori (H. pylori) is acquired in childhood and the prevalence vary greatly in different countries and regions. The study aimed to investigate the characteristics of H. pylori infection among children with gastrointestinal symptoms in Hangzhou, a representative city of eastern China.

Methods

A systematic surveillance of H. pylori infection according to the ¹³C-urea breath test was conducted from January 2007 to December 2014 in the Children’s hospital, Zhejiang University School of Medicine. The demographic information and main symptoms of every subject were recorded.

Results

A total of 12,796 subjects were recruited and 18.6% children evaluated as H. pylori positive. The annual positive rates decreased from 2007 to 2014 (χ² = 20.461, p < 0.01). The positive rates were 14.8%, 20.2% and 25.8% in 3–6, 7–11 and 12–17 years age group respectively, which increased with age (χ² = 116.002, p < 0.01). And it was significantly higher in boys than girls (χ² = 15.090, p < 0.01). Multivariate logistic regression identified possible risk factors for H. pylori infection. Age, gender, gastrointestinal symptoms and history of H. pylori infected family member were all significantly associated with H. pylori infection (all p < 0.05).

Conclusions

H. pylori infection rates in children with gastrointestinal symptoms were lower than most of those reported in mainland China. Further studies are required to determine the prevalence in the general population. Comprehensively understanding of the characteristics and the possible risk factors of H. pylori infection will be helpful to its management strategies in children in China.

Moonlighting of Helicobacter pylori catalase protects against complement-mediated killing by utilising the host molecule vitronectin

Helicobacter pylori is an important human pathogen and a common cause of peptic ulcers and gastric cancer. Despite H. pylori provoking strong innate and adaptive immune responses, the bacterium is able to successfully establish long-term infections. Vitronectin (Vn), a component of both the extracellular matrix and plasma, is involved in many physiological processes, including regulation of the complement system. The aim of this study was to define a receptor in H. pylori that binds Vn and determine the significance of the interaction for virulence. Surprisingly, by using proteomics, we found that the hydrogen peroxide-neutralizing enzyme catalase KatA is a major Vn-binding protein. Deletion of the katA gene in three different strains resulted in impaired binding of Vn. Recombinant KatA was generated and shown to bind with high affinity to a region between heparin-binding domain 2 and 3 of Vn that differs from previously characterised bacterial binding sites on the molecule. In terms of function, KatA protected H. pylori from complement-mediated killing in a Vn-dependent manner. Taken together, the virulence factor KatA is a Vn-binding protein that moonlights on the surface of H. pylori to promote bacterial evasion of host innate immunity.

Helicobacter Pylori Infection: Diagnostic Strategies in Primary Diagnosis and After Therapy

Accurate diagnosis of Helicobacter pylori infection pre- and post-treatment is mandatory in the current era of decreasing prevalence and increasing antibiotic resistance. The diagnostic performance of most tests is poorer in clinical situations with low bacterial density which is seen in conditions such as atrophic gastritis or intake of antisecretory and antibiotic medications. Noninvasive tests require less cost and resource but provide excellent accuracy; however, endoscopy with testing of gastric biopsy specimens is indicated where alarming symptoms are present or antibiotic susceptibility testing by culture is desired. Newer modalities such as polymerase chain reaction testing provide additional virulence and antibiotic sensitivity profiling. This article outlines new developments and the key parameters of each test, as careful selection of test modality within the clinical context is required for adequate management of infected symptomatic patients.

Quinolone-based first, second and third-line therapies for Helicobacter pylori

Helicobacter pylori (H. pylori) is a very common bacterium that infects about 50% of the world population in urban areas and over 90% of people living in rural and developing countries. Fluoroquinolones, a class of antimicrobials, have been extensively used in eradication regimens for H. pylori. Levofloxacin is the most commonly used, and in second-line regimens, is one of the most effective options. However, an increasing resistance rate of H. pylori to fluoroquinolones is being observed, that will likely affect their effectiveness in the near future. Other novel fluoroquinolone molecules, such as moxifloxacin, sitafloxacin, gatifloxacin and gemifloxacin, have been proposed and showed encouraging results in vitro, although data on their clinical use are still limited. Further studies in large sample trials are needed to confirm their safety and efficacy profile in clinical practice.

Prevalence and risk factors of Helicobacter pylori infection in asymptomatic Chinese children: a prospective, cross-sectional, population-based study

BACKGROUND

Limited research has been published on current Helicobacter pylori infection rate in asymptomatic children in China.

AIM

To assess current Helicobacter pylori infection rate, distribution characteristics and risk factors in Chinese asymptomatic children.

METHODS

A prospective, cross-sectional, population-based study was performed from 2009 to 2011 in three cities of China. Helicobacter pylori infection was diagnosed by a stool antigen test. Multi-stage cluster random sampling was used to select asymptomatic children including neonates. Socioeconomic details were obtained through a standardised questionnaire.

RESULTS

Among total of 3491 children (0-18 years), the global infection rate was 6.8% and there were no significant differences between genders. Age specific infection rate between regions was significantly different (P < 0.05). The infection rate significantly increased with age (P for trend <0.01). It was low during the newborn (0.6%) to preschool period and was significantly increased in high school students (13.5%) (P < 0.01). Multivariable regression indicated that hand sanitisation, individually served meals, higher education level of mother, above average living space and residence in urban areas were significantly protective against infection (OR 0.749, 0.698, 0.720, 0.838 and 0.770 respectively). Conversely, consuming meals in unsanitised conditions, sharing towels, receiving pre-chewed food from the mother, artificial feeding and family history of gastrointestinal disease were significantly associated with the risk of infection (OR 1.200, 1.965, 2.002, 1.071 and 2.093 respectively).

CONCLUSIONS

Helicobacter pylori infection rate increases with age in Chinese asymptomatic children and is common after 10 years of age. The rate of infection is related to socioeconomic status.

Helicobacter pylori Antibody Titer and Gastric Cancer Screening

The "ABC method" is a serum gastric cancer screening method, and the subjects were divided based on H. pylori serology and atrophic gastritis as detected by serum pepsinogen (PG): Group A [H. pylori (-) PG (-)], Group B [H. pylori (+) PG (-)], Group C [H. pylori (+) PG (+)], and Group D [H. pylori (-) PG (+)]. The risk of gastric cancer is highest in Group D, followed by Groups C, B, and A. Groups B, C, and D are advised to undergo endoscopy, and the recommended surveillance is every three years, every two years, and annually, respectively. In this report, the reported results with respect to further risk stratification by anti-H. pylori antibody titer in each subgroup are reviewed: (1) high-negative antibody titer subjects in Group A, representing posteradicated individuals with high risk for intestinal-type cancer; (2) high-positive antibody titer subjects in Group B, representing active inflammation with high risk for diffuse-type cancer; and (3) low-positive antibody titer subjects in Group C, representing advanced atrophy with increased risk for intestinal-type cancer. In these subjects, careful follow-up with intervals of surveillance of every three years in (1), every two years in (2), and annually in (3) should be considered.

An infrared spectroscopy method to detect ammonia in gastric juice

Ammonia in gastric juice is considered a potential biomarker for Helicobacter pylori infection and as a factor contributing to gastric mucosal injury. High ammonia concentrations are also found in patients with chronic renal failure, peptic ulcer disease, and chronic gastritis. Rapid and specific methods for ammonia detection are urgently required by the medical community. Here we present a method to detect ammonia directly in gastric juice based on Fourier transform infrared spectroscopy. The ammonia dissolved in biological liquid samples as ammonium ion was released in air as a gas by the shifting of the pH equilibrium of the ammonium/ammonia reaction and was detected in line by a Fourier transform infrared spectroscopy system equipped with a gas cell for the quantification. The method developed provided high sensitivity and selectivity in ammonia detection both in pure standard solutions and in a simulated gastric juice matrix over the range of diagnostic concentrations tested. Preliminary analyses were also performed on real gastric juice samples from patients with gastric mucosal injury and with symptoms of H. pylori infection, and the results were in agreement with the clinicopathology information. The whole analysis, performed in less than 10 min, can be directly applied on the sample without extraction procedures and it ensures high specificity of detection because of the ammonia fingerprint absorption bands in the infrared spectrum. This method could be easily used with endoscopy instrumentation to provide information in real time and would enable the endoscopist to improve and integrate gastroscopic examinations.

Helicobacter Pylori Infection is Positively Associated with Metabolic Syndrome in Taiwanese Adults: a Cross-Sectional Study

BACKGROUND

Helicobacter pylori infection and metabolic syndrome have been reported to be positively associated. However, only a few studies have focused on this issue, and H. pylori serum antigen was used to diagnose infection in most of them. We aimed to investigate the association between metabolic syndrome factors and H. pylori infection, as diagnosed via a (13)C-urea breath test.

MATERIALS AND METHODS

This cross-sectional study consisted of 3578 subjects (18-64 years old) enrolled from one health management center between 2008 and 2013. H. pylori infection was defined as a positive urea breath test. The risk of metabolic syndrome from H. pylori infection was assessed using a multiple logistic regression model.

RESULTS

The prevalence of the H. pylori was similar in both genders (20.6% in men and 19.7% in women). H. pylori -infected participants had significantly higher body mass index, fasting glucose, low-density lipoprotein, and triglycerides, and lower high-density lipoprotein (p < 0.05), than uninfected ones (p < 0.05). The prevalence of metabolic syndrome was higher in H. pylori -infected subjects than uninfected ones (men: 12.4% vs. 7.4%, p < 0.001; women: 7.4% vs. 2.5%, p < 0.001). Furthermore, H. pylori infection prevalence increased with metabolic score (P for trend <0.001, both sexes). Moreover, the association between metabolic syndrome and UBT positivity was significant in females (OR 1.91, 95% CI:1.03-3.53), but only borderline significant in males (OR 1.38, 95% CI: 0.97-1.95).

CONCLUSION

H. pylori infection is positively associated with metabolic syndrome, especially in females. The causal relationship between H. pylori infection and metabolic syndrome warrants further investigation.

Probiotics for standard triple Helicobacter pylori eradication: a randomized, double-blind, placebo-controlled trial

The primary objective in the study is determination of efficacy of probiotic preparation as a supportive therapy in eradication of Helicobacter pylori.The study was multicenter, prospective, randomized, placebo controlled, and double-blind. The subjects first filled out a specially designed questionnaire to assess the severity of the 10 symptoms, which can be related to eradication therapy to be monitored during the trial. Each subject then received 28 capsules of probiotic preparation or matching placebo capsules, which they were supposed to take over the following 14 days, twice a day, at least 2 hours prior to or after the antibiotic therapy administration.A total of 804 patients were enrolled in the trial, of which 650 (80.85%) were included in the analysis. The results show a significantly larger share of cured subjects in the probiotic arm versus the placebo arm (87.38% vs 72.55%; P < 0.001). Additionally, presence and intensity of epigastric pain, bloating, flatulence, taste disturbance, loss of appetite, nausea, vomiting, heartburn, rash, and diarrhea were monitored over the study period. At 15 days postinclusion, probiotic treatment was found superior to placebo in 7 of 10 mentioned symptoms. Average intensity for symptoms potentially related to antibiotic therapy was significantly higher in the placebo group, 0.76 vs 0.55 (P < 0.001).Adding probiotics to the standard triple therapy for H pylori eradication significantly contributes to treatment efficacy and distinctly decreases the adverse effects of therapy and the symptoms of the underlying disease.

Probiotics in Helicobacter pylori eradication therapy: A systematic review and meta-analysis

AIM: To summarize the evidence from randomized controlled trials (RCTs) regarding the effect of probiotics by using a meta-analytic approach.

METHODS: In July 2013, we searched PubMed, EMBASE, Ovid, the Cochrane Library, and three Chinese databases (Chinese Biomedical Literature Database, Chinese Medical Current Content, and Chinese Scientific Journals database) to identify relevant RCTs. We included RCTs investigating the effect of a combination of probiotics and standard therapy (probiotics group) with standard therapy alone (control group). Risk ratios (RRs) were used to measure the effect of probiotics plus standard therapy on Helicobacter pylori (H. pylori) eradication rates, adverse events, and patient compliance using a random-effect model.

RESULTS: We included data on 6997 participants from 45 RCTs, the overall eradication rates of the probiotic group and the control group were 82.31% and 72.08%, respectively. We noted that the use of probiotics plus standard therapy was associated with an increased eradication rate by per-protocol set analysis (RR = 1.11; 95%CI: 1.08-1.15; P < 0.001) or intention-to-treat analysis (RR = 1.13; 95%CI: 1.10-1.16; P < 0.001). Furthermore, the incidence of adverse events was 21.44% in the probiotics group and 36.27% in the control group, and it was found that the probiotics plus standard therapy significantly reduced the risk of adverse events (RR = 0.59; 95%CI: 0.48-0.71; P < 0.001), which demonstrated a favorable effect of probiotics in reducing adverse events associated with H. pylori eradication therapy. The specific reduction in adverse events ranged from 30% to 59%, and this reduction was statistically significant. Finally, probiotics plus standard therapy had little or no effect on patient compliance (RR = 0.98; 95%CI: 0.68-1.39; P = 0.889).

CONCLUSION: The use of probiotics plus standard therapy was associated with an increase in the H. pylori eradication rate, and a reduction in adverse events resulting from treatment in the general population. However, this therapy did not improve patient compliance.

Association between Helicobacter pylori Infection and Chronic Urticaria: A Meta-Analysis

Background. Some studies have shown the possible involvement of Helicobacter pylori (H. pylori) infection in chronic urticaria, but the relationship remains controversial. The aim of this meta-analysis was to quantitatively assess the association between H. pylori infection and chronic urticaria. Methods. Observational studies comparing the prevalence of H. pylori infection in patients with chronic urticaria and control subjects were identified through a systematic search in MEDLINE and EMBASE up to July 2014. H. pylori infection was confirmed by serological or nonserological tests. For subgroup analyses, studies were separated by region, publication year, and H. pylori detection method to screen the potential factors resulting in heterogeneity. Results. 16 studies involving 965 CU cases and 1235 controls were included. Overall, the prevalence of H. pylori infection was higher in urticarial patients than in controls (OR = 1.66; 95% CI: 1.12–2.45; P = 0.01). This result persisted in subanalysis of nine high-quality studies (OR = 1.36; 95% CI: 1.03–1.80; P = 0.03). Subgroup analysis showed that detection method of H. pylori is also a potential influential factor for the overall results. Conclusions. Our present meta-analysis suggests that H. pylori infection is significantly, though weakly, associated with an increased risk of chronic urticaria.

Efficacy of real-time PCR-based detection of Helicobacter pylori infection and genotypic resistance-guided quadruple therapy as the first-line treatment for functional dyspepsia with Helicobacter pylori infection

BACKGROUND

The eradication rate of Helicobacter pylori is steadily decreasing because of increasing resistance to clarithromycin. According to the new version of Maastricht IV guidelines, molecular tests can be performed as a substitute for bacterial culture and the standard clarithromycin susceptibility test for the detection of H. pylori and clarithromycin resistance directly on gastric biopsy samples.

OBJECTIVE

To evaluate the clinical efficacy of H. pylori detection using a molecular test and treatment outcomes of the clarithromycin-based genotypic resistance test.

MATERIALS AND METHODS

A total of 385 patients diagnosed with functional dyspepsia were recruited in this clinical trial. Total DNA was extracted from formalin-fixed paraffin-embedded samples and prepared for a molecular test and H. pylori detection was performed simultaneously by modified Giemsa staining. Genotypically sensitive patients with positive H. pylori were treated by quadruple therapy: bismuth potassium citrate, rabeprazole, amoxicillin, and clarithromycin (BRAC) and genotypically resistant individuals were treated by bismuth potassium citrate, rabeprazole, amoxicillin, and furazolidone (BRAF) twice daily for 7 consecutive days. The eradication rate of H. pylori was assessed using the C-urea breath test at 6 weeks after treatment.

RESULTS

The prevalence of H. pylori infection in functional dyspepsia patients was 35.3% (136/385), 29.1% for women (53/182) and 40.9% for men (83/203). The sensitivities of real-time PCR and histological examinations were 95.6% (130/136) and 69.9% (95/136). Forty-one samples were found to be positive by real-time PCR alone and six by histological examination alone, the majority of which (32/41, 5/6) were identified as grade 1 multiplicity of infection. The overall resistance rate to clarithromycin was 37.7% (49/130): 37.3% (19/51) for women and 38.0% for men (30/79). Eighty-nine patients with positive H. pylori detected by both real-time PCR and histological examinations received quadruple therapies. For the intention-to-treat analysis, the eradication rates of BRAC and BRAF were 98% (52/53) and 92% (33/36), or 100% (52/52) and 94% (33/35) for per-protocol analysis.

CONCLUSION

Real-time PCR is efficacious for H. pylori detection and genotypic resistance-guided quadruple therapy has a high efficacy in treating functional dyspepsia with H. pylori infection.

Efficacy of reduced-dose regimen of a capsule containing bismuth subcitrate, metronidazole, and tetracycline given with amoxicillin and esomeprazole in the treatment of Helicobacter Pylori infection

It is well known that triple therapy for Helicobacter pylori is losing efficacy worldwide. A regimen containing proton pump inhibitor and multiple-dose capsules of bismuth, metronidazole, and tetracycline has proven efficacy. In addition, a literature review on dosage of previous regimens shows that half-dose clarithromycin-based regimens are equally effective to full-dose regimens. However, the applicability of dose reduction to bismuth-based therapy is unknown. This communication shows that a reduced-dose bismuth-based regimen fails to achieve acceptable eradication rates.

Helicobacter pylori infection decreases metformin tolerance in patients with type 2 diabetes mellitus

AIM

This study assessed whether Helicobacter pylori infection could influence metformin tolerance in patients with type 2 diabetes mellitus.

SUBJECTS AND METHODS

Demographic, anthropometric, ultrasound, and laboratory data were obtained from 415 metformin-naive patients with diabetes. H. pylori infection was assessed based on the (13)C-labeled urea breath test ((13)C-UBT). The study duration was 4 weeks, and all subjects started metformin from 500 mg/day to 1,500 mg/day progressively. Gastrointestinal side effects were assessed each week, and the metformin doses were adjusted by the compliance. Gastrointestinal side effects were compared between H. pylori-positive and -negative groups.

RESULTS

According to the (13)C-UBT results, 220 patients were categorized as H. pylori negative versus 195 as H. pylori positive. At baseline, the scoring of gastrointestinal symptoms showed no statistical difference between the two groups. After 4 weeks, for gastrointestinal symptoms such as abdominal pain, nausea, bloating, and anorexia, the respective percentages in H. pylori-positive and -negative subjects were 44.6% versus 21.8% (P < 0.01), 20.0% versus 9.6% (P < 0.01), 47.7% versus 23.2% (P < 0.01), and 32.8% versus 12.3% (P < 0.01). The final metformin dose was 951.28 ± 661.1 mg in H. pylori-positive subjects, significantly less than that in H. pylori-negative subjects (1,209.09 ± 522.91 mg) (P < 0.01). On multivariate analysis, female gender, H. pylori infection, body mass index, triglycerides, age, and low-density lipoprotein-cholesterol were the independent parameters associated with any gastrointestinal symptoms.

CONCLUSIONS

Patients with diabetes having H. pylori infection demonstrated more gastrointestinal side effects than those without H. pylori infection after taking metformin. Furthermore, female gender, H. pylori infection, body mass index, triglycerides, age, and low-density lipoprotein-cholesterol are independent determinants of metformin's side effects.

Age, period, and cohort effects on gastric cancer mortality

BACKGROUND

The incidence of gastric cancer varies both within and among populations and can change rapidly without a corresponding decline in Helicobacter pylori prevalence. Here, we describe the changes in gastric cancer mortality in Japan in relation to age-period-cohort effects as well as the decline in H. pylori prevalence.

METHODS

We used data from Japanese for men and women aged 30-94 for birth years 1875-1970 (calendar time 1950-2000) to observe the age, period and cohort effects on gastric cancer mortality rates. Additionally, we used Poisson regression to simultaneously adjust for concurrent age, period and cohort effects as well as for declining H. pylori prevalence in the Japanese population.

RESULTS

There was an approximate 60 % decline in gastric cancer mortality between 1965 and 1995. Detailed age, period and cohort analyses and Poisson regression analysis showed these factors interact in complex ways, analyses focused on one or two of these effects, such as birth cohort without considering concurrent age and period would obscure important interactions that affected different age groups at different times to produce this composite effect.

CONCLUSION

The underlying complexity in population-disease dynamics requires population-specific descriptions of trends using multiple methods to provide an in-depth analysis while simultaneously allowing for necessary statistical adjustments as well as identification of interactions. More thorough descriptions of the population-specific general trends in relation to changes in the population structure (age-period-cohort) enable better prevention and health care policy planning, and further, the descriptions enable hypothesis generation regarding causes of population-specific disease patterns.

Seminal Helicobacter pylori treatment improves sperm motility in infertile asthenozoospermic men

OBJECTIVE

To assess the effect of treatment of seminal Helicobacter pylori in infertile asthenozoospermic men.

METHODS

In all, 223 infertile asthenozoospermic men were consecutively selected. They were subjected to history taking, clinical examination, semen analysis, and estimation of H pylori IgA antibodies in their seminal fluid. Infertile men with high seminal H pylori IgA were subjected to triple drug treatment, omeprazole, 20 mg; tinidazole, 500 mg; and clarithromycin, 250 mg twice a day for 2 weeks. Semen analysis as well as H pylori IgA antibodies was estimated after 3 months.

RESULTS

In all, 22 of 223 men (9.87%) demonstrated H pylori IgA antibodies in their seminal plasma. After treatment, mean seminal H pylori IgA levels demonstrated significant decrease (1.55 ± 0.4 vs 0.52 ± 0.26; 95% confidence interval, 0.83-1.21; P = .001) concomitant with improved progressive as well as nonprogressive sperm motility. H pylori IgA antibodies demonstrated significant negative correlation with progressive sperm motility, nonprogressive sperm motility, normal sperm morphology, and significant positive correlation with immotile sperm motility.

CONCLUSION

H pylori treatment significantly improves sperm motility in infertile asthenozoospermic men with elevated seminal H pylori IgA.

Standard triple therapy for Helicobacter pylori infection in China: a meta-analysis

AIM

To assess the efficacy and safety of standard triple therapy compared with other pre-existing and new therapies in China.

METHODS

Literature searches were conducted in the following databases: PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, the VIP database, the China National Knowledge Infrastructure database, and the Chinese Biomedical Database. A meta-analysis of all randomized controlled trials (RCTs) comparing standard triple therapy for the eradication of Helicobacter pylori with pre-existing and new therapies in China was performed using Comprehensive Meta-Analysis 2.0. There were 49 studies that met our criteria and the qualities of these studies were assessed using the Jadad scale. The Mantel-Haenszel method was used for pooling dichotomous data. We also conducted subgroup analyses according to age, duration of treatment and drug type. Sensitivity analyses and a cumulative meta-analysis were also performed with CMA 2.0. Publication bias was evaluated using Egger's test, Begg's test or a funnel plot.

RESULTS

A total of 49 RCTs including 8332 patients were assessed. This meta-analysis showed that standard triple therapy with proton pump inhibitors (PPIs), amoxicillin (AMO) and clarithromycin (CLA) was inferior to sequential therapy [relative risk (RR) = 0.863; 95% confidence interval (CI): 0.824-0.904], but was not superior to quadruple therapy (RR = 1.073; 95%CI: 0.849-1.357) or other triple therapies (RR = 1.01; 95%CI: 0.936-1.089). The meta-analysis also suggested that standard triple therapy is slightly more effective than dual therapy (RR = 1.14; 95%CI: 0.99-1.31). However, the differences were not statistically significant. We removed the only trial with a regimen lasting 14 d by sensitivity analysis and found that 7-d standard triple therapy was superior to 7-d dual therapy (RR = 1.222; 95%CI: 1.021-1.461). Moreover, a sub-analysis based on the duration of quadruple therapy indicated that the 7-d and 10-d standard triple therapies were inferior to sequential therapy (RR = 0.790; 95%CI: 0.718-0.868; RR = 0.917; 95%CI: 0.839-1.002, respectively). Additionally, there were no significant differences in cure rate or adverse events among standard triple therapy, quadruple therapy, and other triple therapies (RR = 0.940; 95%CI: 0.825-1.072; RR = 1.081; 95%CI: 0.848-1.378, respectively). Standard triple therapy had a higher occurrence of side effects than sequential therapy (RR = 1.283; 95%CI: 1.066-1.544).

CONCLUSION

The eradication rates with a standard triple therapy consisting of PPI, AMO, and CLA are suboptimal in China, and new treatment agents need to be developed.

Efficacy and safety of ecabet sodium as an adjuvant therapy for Helicobacter pylori eradication: a systematic review and meta-analysis

BACKGROUND

Several studies have reported that the application of ecabet sodium during the eradication of Helicobacter pylori can improve the eradication rate and reduce therapy-associated side effects. However, the efficacy and safety of this therapy are controversial.

OBJECTIVES

To determine whether ecabet sodium improves the eradication rate of H. pylori and examine treatment safety by conducting a meta-analysis based on randomized controlled trials (RCTs).

METHODS

Literature searches were conducted in the following databases: PubMed, Embase, the Cochrane Library, the Science Citation Index, the China National Knowledge Infrastructure Database, and the Wanfang Database. A meta-analysis of all RCTs comparing ecabet sodium supplementation with nonecabet sodium-containing therapy was performed.

RESULTS

Thirteen RCTs that included a total of 1808 patients were assessed. The meta-analysis showed that the eradication rate in the ecabet sodium-containing quadruple therapy group was higher than that in the standard triple therapy group (84.5% vs 74.55%, OR 1.757 (95%CI: 1.307 to 2.362), p < .001). The analysis also showed that the eradication rate in the ecabet sodium-containing triple therapy group was significantly higher than that in the PPI plus amoxicillin or clarithromycin therapy group (74.6% vs 43.9%,OR 3.727 (95%CI: 2.320 to 5.988), p < .001)(ITT), (74.6% vs 43.9%,OR 3.863 (95%CI: 2.369 to 6.298), p < .001) (PP). Furthermore, our meta-analysis suggested that the occurrence of side effects did not significantly differ between patients receiving ecabet sodium-containing therapy and patients receiving nonecabet sodium-containing therapy (14.0% vs 13.3%, OR 1.055 (95%CI: 0.632 to 1.759), p = .839).

CONCLUSION

Supplementation with ecabet sodium during H. pylori eradication therapy improves the eradication rate. The use of ecabet sodium does not increase the side effects based on our meta-analysis.

Investigation of C3-C10 aldehydes in the exhaled breath of healthy subjects using selected ion flow tube-mass spectrometry (SIFT-MS)

Aldehydes have attracted great scientific and clinical interest as potential disease biomarkers. We have investigated selected ion flow tube-mass spectrometry (SIFT-MS) in detecting and quantifying C3 to C10 saturated aldehydes (propanal, butanal, pentanal, hexanal, heptanal, octanal, nonanal and decanal) from the exhaled breath of 26 healthy human volunteers. To assess the reliability of the Nalophan® bag sampling method employed, the water level in the breath sample was measured up to 4 h after collection and showed no significant degradation. Propanal was found to be the most abundant aldehyde in the exhaled breath of healthy volunteers. For the C4-C10 aldehydes, their median concentrations were all less than 3 ppbv, demonstrating only trace quantities are present in the exhaled breath of the 26 healthy volunteers.

Helicobacter pylori infection and drugs malabsorption

Drug absorption represents an important factor affecting the efficacy of oral drug treatment. Gastric secretion and motility seem to be critical for drug absorption. A causal relationship between impaired absorption of orally administered drugs and Helicobacter pylori (H. pylori) infection has been proposed. Associations have been reported between poor bioavailability of l-thyroxine and l-dopa and H. pylori infection. According to the Maastricht Florence Consensus Report on the management of H. pylori infection, H. pylori treatment improves the bioavailability of both these drugs, whereas the direct clinical benefits to patients still await to be established. Less strong seems the association between H. pylori infection and other drugs malabsorption, such as delavirdine and ketoconazole. The exact mechanisms forming the basis of the relationship between H. pylori infection and impaired drugs absorption and/or bioavailability are not fully elucidated. H. pylori infection may trigger a chronic inflammation of the gastric mucosa, and impaired gastric acid secretion often follows. The reduction of acid secretion closely relates with the wideness and the severity of the damage and may affect drug absorption. This minireview focuses on the evidence of H. pylori infection associated with impaired drug absorption.

Helicobacter pylori infection - recent developments in diagnosis

Considering the recommended indications for Helicobacter pylori (H. pylori) eradication therapy and the broad spectrum of available diagnostic methods, a reliable diagnosis is mandatory both before and after eradication therapy. Only highly accurate tests should be used in clinical practice, and the sensitivity and specificity of an adequate test should exceed 90%. The choice of tests should take into account clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy and the availability of the tests. This review concerns some of the most recent developments in diagnostic methods of H. pylori infection, namely the contribution of novel endoscopic evaluation methodologies for the diagnosis of H. pylori infection, such as magnifying endoscopy techniques and chromoendoscopy. In addition, the diagnostic contribution of histology and the urea breath test was explored recently in specific clinical settings and patient groups. Recent studies recommend enhancing the number of biopsy fragments for the rapid urease test. Bacterial culture from the gastric biopsy is the gold standard technique, and is recommended for antibiotic susceptibility test. Serology is used for initial screening and the stool antigen test is particularly used when the urea breath test is not available, while molecular methods have gained attention mostly for detecting antibiotic resistance.

Fluoroquinolone-based protocols for eradication of Helicobacter pylori

Helicobacter pylori (H. pylori) is a widespread pathogen infecting about 40% of people living in urban areas and over 90% of people living in the developing regions of the world. H. pylori is well-documented as the main factor in the pathogenesis of peptic ulcer disease, chronic gastritis, and gastric malignancies such as cancer and mucosa-associated lymphoid tissue-lymphoma; hence, its eradication is strongly recommended. The Maastricht IV consensus, which focused on the management of H. pylori infection, set important new strategies in terms of treatment approaches, particularly with regards to first- and second-line treatment protocols and led to improved knowledge and understanding of H. pylori resistance to antibiotics. In recent years, various fluoroquinolone-based protocols, mainly including levofloxacin, have been proposed and effectively tested at all therapeutic lines for H. pylori eradication. The aim of the present paper is to review the scientific literature focused on the use of fluoroquinolones in eradicating H. pylori.

Unique features and risk factors of Helicobacter pylori infection at the main children's intermediate school in Rabigh, Saudi Arabia

BACKGROUND

This study was conducted to determine characters and risk factors of Helicobacter pylori infection and its relationship with recurrent abdominal pain and other gastrointestinal symptoms at the main children's intermediate school in Rabigh, Saudi Arabia.

METHODS

A cross-sectional study was conducted at a boys' intermediate school. A questionnaire for the gastrointestinal (GI) symptoms and relevant personal and socioeconomic risk factors related to H. pylori infection was distributed followed by H. pylori IgG antibody assay and 14C urea breath test to detect active infection.

RESULTS

H. pylori was diagnosed by positive urea breath test in 51.5 % of students. H. pylori infection was symptomatic with at least one upper GI symptom in 89.7 % of infected students which was higher than symptomatic cases reported in any other study. H. pylori-infected students had significantly more association with the presence of any upper GI symptom (p < 0.001), recurrent abdominal pain (p < 0.001), anorexia (p < 0.001), nausea (p < 0.026), family history of peptic disease (p < 0.001), drinking desalinated municipal water (p < 0.001), lower income (p = 0.02), and eating outside home (p = 0.003) than uninfected students. Logistic regression analysis showed that the most significant predictors of H. pylori infection were presence of any upper GI symptom (OR 5.3, 95 % CI 2.32-15.71), family history of peptic disease (OR 2.2, 95 % CI 1.11-3.9), and drinking desalinated municipal water (OR 2.1, 95 % CI 1.09-3.2).

CONCLUSIONS

This study presented unique features and risk factors of H. pylori infection in 12-15-year-old Saudi boys in Rabigh, and mainly supported the role of H. pylori in causing recurrent abdominal pain.

Virulence genes of Helicobacter pylori in the Dominican Republic

Although the incidence of gastric cancer in the Dominican Republic is not high, the disease remains a significant health problem. We first conducted a detailed analysis of Helicobacter pylori status in the Dominican Republic. In total, 158 patients (103 females and 55 males; mean age 47.1±16.2 years) were recruited. The status of H. pylori infection was determined based on four tests: rapid urease test, culture test, histological test and immunohistochemistry. The status of cagA and vacA genotypes in H. pylori was examined using PCR and gene sequencing. The overall prevalence of H. pylori infection was 58.9 %. No relationship was found between the H. pylori infection rate and the age range of 17-91 years. Even in the youngest group (patients aged <29 years), the H. pylori infection rate was 62.5 %. Peptic ulcer was found in 23 patients and gastric cancer was found in one patient. The H. pylori infection rate in patients with peptic ulcer was significantly higher than that in patients with gastritis (82.6 versus 54.5 %, P<0.01). The cagA-positive/vacA s1m1 genotype was the most prevalent (43/64, 67.2 %). Compared with H. pylori-negative patients, H. pylori-positive patients showed more severe gastritis. Furthermore, the presence of cagA was related to the presence of more severe gastritis. All CagA-positive strains had Western-type CagA. In conclusion, we found that H. pylori infection is a risk factor for peptic ulcer in the Dominican Republic. Patients with cagA-positive H. pylori could be at higher risk for severe inflammation and atrophy.

Helicobacter pylori infection in older people

Since the discovery of Helicobacter pylori (H. pylori) infection as the major cause of gastroduodenal disorders three decades ago, H. pylori has been the focus of active research and debate in the scientific community. Its linkage to several diseases, such as peptic ulcer disease, gastritis and gastric malignancy is incontestable. In particular, it has been noticed that, as the aged population is increasing worldwide, older people are at increased risk of developing several gastroduodenal diseases and related complications. At the same time, gastric cancer is definitely more frequent in elderly than in adult and young people. In addition, it has been showed that peptic ulcer and related complications occur much more commonly in aged individuals than in young people, resulting in a significantly higher mortality. Although this infection plays a crucial role in gastrointestinal disorders affecting all age groups and in particular older people, only a few studies have been published regarding the latter. This article presents an overview of the epidemiology, diagnosis, clinical manifestations and therapy of H. pylori infection in elderly people.

Changing prevalence patterns in endoscopic and histological diagnosis of gastritis? Data from a cross-sectional Central European multicentre study

BACKGROUND AND AIMS

Traditionally, Helicobacter infection is considered to be the most common cause of gastritis. In the cross-sectional Central European histoGERD trial, we assessed the prevalence of different types of gastritis, correlating histological and endoscopic diagnoses.

METHODS

A total of 1123 individuals participated in an observational multicentre study. Endoscopists classified individuals as positive or negative for gastritis and rendered the putative cause. Pathologists evaluated biopsy specimens based upon the Updated Sydney System.

RESULTS

Histological diagnosis of gastritis was made in 639 (56.9%) participants. In all, 210 (18.7%) individuals were diagnosed with Helicobacter gastritis, 215 (19.1%) with post Helicobacter gastritis, 234 (20.8%) with reactive gastropathy, 26 (2.3%) with autoimmune gastritis, and 6 (0.5%) with focally enhanced gastritis related to Crohn's disease. In 46 out of 639 (7.2%) individuals diagnosed with gastritis, combinations of different histological subtypes were noted the most common being reactive gastropathy and post Helicobacter gastritis. Endoscopic diagnosis of gastritis was made in 534 (47.6%) individuals.

CONCLUSIONS

Reactive gastropathy was more common than active Helicobacter gastritis, and the majority of cases attributable to Helicobacter infection were no longer ongoing, i.e. post Helicobacter gastritis. Agreement between histological and endoscopic diagnoses was better in reactive gastropathy than in Helicobacter gastritis.

High prevalence of Helicobacter pylori infection in Behcet's disease

Background

Behcet’s disease (BD) is a multisystem disease of unknown etiology. There are several clues which may indicate an ethiopathogenesis role for Helicobacter pylori infection in this disease.

Methods

In a case control study in an out patient department, 48 patients with BD were compared to age, sex matched controls regarding presence of H. pylori infection by serology and urea breath test (UBT).

Results

Ongoing H. pylori infection was more prevalent among patients with BD using result of UBT with odds ratio of 3.1 (95% CI: 1.34 – 7.26, PV < 0.001).

Conclusion

H. pylori infection may have a role in the pathogenesis of BD.

Cancer incidence and mortality in France over the 1980-2012 period: solid tumors

BACKGROUND

Cancer incidence and mortality estimates for 19 cancers (among solid tumors) are presented for France between 1980 and 2012.

METHODS

Incidence data were collected from 21 local registries and correspond to invasive cancers diagnosed between 1975 and 2009. Mortality data for the same period were provided by the Institut national de la santé et de la recherche médicale. The national incidence estimates were based on the use of mortality as a correlate of incidence. The observed incidence and mortality data were modeled using an age-period-cohort model. The numbers of incident cases and deaths for 2010-2012 are the result of short-term projections.

RESULTS

In 2012, the study estimated that 355,000 new cases of cancer (excluding non-melanoma skin cancer) and 148,000 deaths from cancer occurred in France. The incidence trend was not linear over the study period. After a constant increase from 1980 onwards, the incidence of cancer in men declined between 2005 and 2012. This recent decrease is largely related to the reduction in the incidence of prostate cancer. In women, the rates stabilized, mainly due to a change in breast cancer incidence. Mortality from most cancer types declined over the study period. A combined analysis of incidence and mortality by cancer site distinguished cancers with declining incidence and mortality (e.g., stomach) and cancers with increasing incidence and mortality (e.g., lung cancer in women). Some other cancers had rising incidence but declining mortality (e.g., thyroid).

CONCLUSION

This study reveals recent changes in cancer incidence trends, particularly regarding breast and prostate cancers.

A review of Helicobacter pylori diagnosis, treatment, and methods to detect eradication

Helicobacter pylori (H. pylori) affects nearly half of the world’s population and, thus, is one of the most frequent and persistent bacterial infections worldwide. H. pylori is associated with peptic ulcer disease, gastric ulcers, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Various diagnostic methods exist to detect infection, and the choice of one method or another depends on several factors, such as accessibility, advantages and disadvantages of each method, cost, and the age of patients. Once H. pylori infection is diagnosed, the clinician decides whether treatment is necessity, according to the patient’s clinical condition. Typically, eradication of H. pylori is recommended for treatment and prevention of the infection. Cure rates with the standard triple therapy are acceptable, and effective quadruple therapies, sequential therapies, and concomitant therapies have been introduced as key alternatives to treat H. pylori infection. In this work, we review the main diagnostic methods used to identify H. pylori infection and to confirm eradication of infection. In addition, key factors related to treatment are reviewed.

Helicobacter species infection may be associated with cholangiocarcinoma: a meta-analysis

OBJECTIVE

Since the discovery of Helicobacter species in human biliary system, the association between Helicobacter species infection and cholangiocarcinoma is under debate. This meta-analysis aims to explore this issue.

METHODS

Literature search was carried out to identify all eligible articles. We performed overall meta-analysis of all included studies and subgroup analysis based on regional distribution. Subgroup analysis in the light of detection methods and specimens was also conducted.

RESULTS

Ten case-control studies were included. Overall meta-analysis favoured a significant association between Helicobacter species infection and cholangiocarcinoma (cumulative OR 8.88, 95% CI 3.67-21.49). Subgroup analysis based on geographic distribution indicated that Helicobacter species infection may serve as a risk factor not only in a region with high cholangiocarcinoma incidence (Asia, OR 6.68, 95% CI 2.29-19.49) but also in low incidence region (Europe, OR 14.90, 95% CI 4.79-46.35). The other subgroup analysis showed that PCR was the most effective and efficient method to detect Helicobacter species in surgically resected tissue and bile. There was significant heterogeneity among studies and obvious publication bias.

CONCLUSION

Our meta-analysis supports the possible association between Helicobacter species infection and cholangiocarcinoma. Further investigations are required to clarify the role of Helicobacter species in this malignancy.

Eficacia del método de inmunocromatografía en heces para el diagnóstico de Helicobacter Pylori en pacientes con dispepsia: evaluación preliminar

La infección por Helicobacter pylori se considera una de las afecciones emergentes más importantes del presente siglo, relacionándose estrechamente con las enfermedades del tracto gastroduodenal y como factor predisponente para el carcinoma gástrico. Para su diagnóstico se han empleado pruebas invasiva y no invasivas, entre estas últimas la inmunocromatografía en heces, la cual detecta cualitativamente antígenos de éste patógeno. El objetivo del presente estudio fue determinar la eficacia de una inmunocromatografía para el diagnóstico de la infección por H. pylori en pacientes dispépticos de un centro hospitalario de Cundinamarca. Se realizó un estudio preliminar para evaluar una prueba diagnóstica, tomando pacientes con historia de dispepsia y que presentaran reporte de biopsia gástrica en la historia clínica. Se evaluaron muestras de heces y por medio del rapid test SD Bio Line H. pylori Ag™, se determinó la presencia de antígenos de H. pylori en las muestras fecales. Se evaluaron un total de 33 pacientes: 48,4 % hombres y 51,5% mujeres, la sensibilidad fue de 30% y una especificidad de 84.62%. El valor predictivo positivo se calculó en 75% y el valor predictivo negativo fue de 44 %. La especificad calculada para la prueba es comparable con la encontrada en la literatura, no obstante, debido al intervalo que mostró el índice de confiabilidad haría falta más pruebas que permitan aumentar la confiabilidad de los resultados aquí mostrados.

Choosing optimal first-line Helicobacter pylori therapy: a view from a region with high rates of antibiotic resistance

Helicobacter pylori is a gram-negative, microaerophilic spiral bacillus that is associated with life-threatening diseases such as gastric cancer, gastric MALT lymphoma, and peptic ulcer disease. The definition of an effective therapy is one that achieves at least a 90% eradication rate on a per-protocol basis with the first attempt. Eradication rates of H. pylori have declined to unacceptable levels worldwide, mostly due to antibiotic resistance and standard triple therapy gradually has lost its efficacy in most counties. However, bismuth quadruple therapy, when prescribed properly, has maintained its effectiveness. Alternative first-line regimens such as sequential and concomitant therapy were developed to substitute for standard triple therapy and were highly effective in the countries where they were developed, but proved susceptible to failure in regions with high rates of antibiotic resistance. Antibiotic resistance rates in Russia are high, however there is lack of data regarding comparative efficacy of first-line eradication options. The authors of this review extrapolate the knowledge of H. pylori first-line eradication options in Russia based on data from other countries, as well as from domestic studies. The available data support use of 14-day regimens with concomitant therapy, bismuth quadruple therapy, or furazolidone quadruple therapy for empiric use in adults. In addition, 14-day levofloxacin-containing therapies could be used if resistance is relatively low or lacking as triple therapy or possibly as a 5-day concomitant levofloxacin therapy.

Association between non-alcoholic fatty liver disease, insulin resistance and Helicobacter pylori

Here we report a case of a 55-year Caucasian man, who improved the metabolic profile after the treatment for Helicobacter pylori eradication. In particular, we report the changes in homeostatic model assessment of insulin resistance, fatty liver index and echographic liver pattern. We hypothesize the co-factorial role of H. pylori in the mechanisms involved in non-alcoholic fatty liver disease pathogenesis and insulin resistance, by the cytokine serum changes. If this correlation is confirmed, the H. pylori treatment may represent an option in the clinical management of liver steatosis.

A comparative study of clinicopathological features between chronic cholecystitis patients with and without Helicobacter pylori infection in gallbladder mucosa

Background

Helicobacter pylori has been isolated from 10%–20% of human chronic cholecystitis specimens but the characteristics of “Helicobacter pylori positive cholecystitis” remains unclear. This study aims to compare the clinicopathological features between chronic cholecystitis patients with and without Helicobacter pylori infection in gallbladder mucosa.

Methods

Three hundred and twenty-six chronic cholecystitis patients were divided into two groups according to whether Helicobacter pylori could be detected by culture, staining or PCR for Helicobacter 16s rRNA gene in gallbladder mucosa. Positive samples were sequenced for Helicobacter pylori-specific identification. Clinical parameters as well as pathological characteristics including some premalignant lesions and the expression levels of iNOS and ROS in gallbladder were compared between the two groups.

Results

Helicobacter pylori infection in gallbladder mucosa was detected in 20.55% of cholecystitis patients. These patients had a higher prevalence of acid regurgitation symptoms (p = 0.001), more histories of chronic gastritis (p = 0.005), gastric ulcer (p = 0.042), duodenal ulcer (p = 0.026) and higher presence of Helicobacter pylori in the stomach as compared to patients without Helicobacter pylori infection in the gallbladder mucosa. Helicobacter pylori 16s rRNA in gallbladder and gastric-duodenal mucosa from the same individual patient had identical sequences. Also, higher incidences of adenomyomatosis (p = 0.012), metaplasia (p = 0.022) and higher enhanced expressions of iNOS and ROS were detected in Helicobacter pylori infected gallbladder mucosa (p<0.05).

Conclusions

Helicobacter pylori infection in gallbladder mucosa is strongly associated with Helicobacter pylori existed in stomach. Helicobacter pylori is also correlated with gallbladder premalignant lesions including metaplasia and adenomyomatosis. The potential mechanism might be related with higher ROS/RNS production but needs further investigation.

Extremely high prevalence of Helicobacter pylori infection in Bhutan

AIM: To revealed the prevalence of Helicobacter pylori (H. pylori) infection in the Bhutanese population.

METHODS: We recruited a total of 372 volunteers (214 females and 158 males; mean age of 39.6 ± 14.9 years) from three Bhutanese cities (Thimphu, Punaka, and Wangdue). The status of H. pylori infection was determined based on five different tests: the rapid urease test (CLO test), culture, histology, immunohistochemistry (IHC), and serum anti H. pylori-antibody.

RESULTS: The serological test showed a significantly higher positive rate compared with the CLO test, culture, histology and IHC (P < 0.001, P < 0.001, P = 0.01, and P = 0.01, respectively). When the subjects were considered to be H. pylori positive in the case of at least one test showing a positive result, the overall prevalence of H. pylori infection in Bhutan was 73.4%. The prevalence of H. pylori infection significantly decreased with age (P < 0.01). The prevalence of H. pylori infection was lower in Thimphu than in Punakha and Wangdue (P = 0.001 and 0.06, respectively). The prevalence of H. pylori infection was significantly higher in patients with peptic ulcers than in those with gastritis (91.4% vs 71.3%, P = 0.003).

CONCLUSION: The high incidence of gastric cancer in Bhutan may be attributed to the high prevalence of H. pylori infection.

Association between Helicobacter pylori infection and pancreatic cancer development: a meta-analysis

BACKGROUND

Pancreatic cancer is one of the most troublesome malignancies with dismal prognosis. H. pylori has been recognized as a type I carcinogen. Several studies have evaluated the association between H. pylori infection and pancreatic cancer development, however, the conclusions are inconsistent.

METHODS

Literature search was carried out in PubMed, EMBASE, Cochrane Library and CNKI databases to identify eligible researches. We performed overall meta-analysis of all studies included and subgroup analysis based on regional distribution. Quality of the studies (assessed by Newcastle-Ottawa quality assessment scale for case-control studies) and CagA+ strains of H. pylori were taken into consideration, and we conducted additional analyses including high-quality researches and those concerning CagA+ H. pylori respectively.

RESULTS

9 studies involving 3033 subjects (1083 pancreatic cancer cases, 1950 controls) were included. Summary OR and 95%CI of the overall meta-analysis of all included studies were 1.47 and 1.22-1.77, pooled data of the 4 high-quality studies were OR 1.28, 95%CI 1.01-1.63. OR of the 5 studies examined CagA+ strains was 1.42, corresponding 95%CI was 0.79 to 2.57. Summary estimates of subgroup analysis based on regional distribution are as follows, Europe group: OR 1.56, 95%CI 1.15-2.10; East Asia group: OR 2.01, 95%CI 1.33-3.02; North America group: OR 1.17, 95%CI 0.87-1.58. There was not obvious heterogeneity across the 9 studies. No publication bias was detected.

CONCLUSION

H. pylori infection is significantly, albeit weakly, associated with pancreatic cancer development. The association is prominent in Europe and East Asia, but not in North America. CagA+ H. pylori strains appear not to be associated with pancreatic cancer. However, more studies, especially prospective studies, are needed to validate our results.