Review: Helicobacter pylori and non-malignant upper gastrointestinal diseases

Ten-Day Vonoprazan-Amoxicillin Dual Therapy vs Standard 14-Day Bismuth-Based Quadruple Therapy for First-Line Helicobacter pylori Eradication: A Multicenter Randomized Clinical Trial

INTRODUCTION

Whether 10-day short-course vonoprazan-amoxicillin dual therapy (VA-dual) is noninferior to the standard 14-day bismuth-based quadruple therapy (B-quadruple) against Helicobacter pylori eradication has not been determined. This trial aimed to compare the eradication rate, adverse events, and compliance of 10-day VA-dual regimen with standard 14-day B-quadruple regimen as first-line H. pylori treatment.

METHODS

This prospective randomized clinical trial was performed at 3 institutions in eastern China. A total of 314 treatment-naive, H. pylori -infected patients were randomly assigned in a 1:1 ratio to either 10-day VA-dual group or 14-day B-quadruple group. Eradication success was determined by 13 C-urea breath test at least 4 weeks after treatment. Eradication rates, adverse events, and compliance were compared between groups.

RESULTS

Eradication rates of VA-dual and B-quadruple groups were 86.0% and 89.2% ( P = 0.389), respectively, by intention-to-treat (ITT) analysis; 88.2% and 91.5% ( P = 0.338), respectively, by modified ITT analysis; and 90.8% and 91.3% ( P = 0.884), respectively, by per-protocol (PP) analysis. The efficacy of the VA-dual remained noninferior to B-quadruple therapy in all ITT, modified ITT, and PP analyses. The incidence of adverse events in the VA-dual group was significantly lower compared with that in the B-quadruple group ( P < 0.001). Poor compliance contributed to eradication failure in the VA-dual group ( P < 0.001), while not in the B-quadruple group ( P = 0.110).

DISCUSSION

The 10-day VA-dual therapy provided satisfactory eradication rates of >90% (PP analysis) and lower rates of adverse events compared with standard 14-day B-quadruple therapy as first-line H. pylori therapy.

TRAIL REGISTRATION NUMBER

ChiCTR2300070100.

The association between Helicobacter pylori and gastrointestinal disorders during pregnancy: A Multicenter retrospective study

BACKGROUND

Some gastrointestinal disorders may be associated with Helicobacter pylori infection, which not only affect maternal health, but may also lead to adverse pregnancy outcomes. We aim to explore the association between H. pylori and gastrointestinal disorders in pregnant women.

MATERIALS AND METHODS

In total, 503 patients were retrospectively analyzed and divided into the H. pylori-uninfected group, the H. pylori-infected group, or the H. pylori-eradicated group. We analyzed the influence of H. pylori on gastrointestinal diseases during pregnancy among the groups, as well as the severity, symptoms, laboratory tests of the H. pylori-related diseases.

RESULTS

Pregnant women with H. pylori infection had higher risk of nausea and vomiting of pregnancy (NVP) (p < 0.001), severe NVP(p = 0.012), hyperemesis gravidarum (p = 0.027), hematemesis (p = 0.018), hyponatremia (p = 0.033), as well as functional dyspepsia symptoms including epigastric pain (p = 0.004), bloating (p = 0.024), and feeling full quickly in a meal (p = 0.031) compared with those without H. pylori infection. While the prevalence of NVP (p = 0.024), severe NVP (p = 0.009), epigastric pain (p = 0.037), and bloating (p = 0.032) were lower in H. pylori-eradicated pregnant women than in H. pylori-infected women. In addition, pregnant women with H. pylori infection had higher risk of spontaneous preterm birth than whom without H. pylori infection (p = 0.033).

CONCLUSIONS

Helicobacter pylori infection was associated with higher risks of NVP, severe NVP, hyperemesis gravidarum, functional dyspepsia, and spontaneous preterm birth in pregnant women.

A randomized clinical study on the efficacy of vonoprazan combined with amoxicillin duo regimen for the eradication of Helicobacter pylori

BACKGROUND

Helicobacter pylori (H pylori) can cause gastritis, peptic ulcers, gastric cancer, and many other gastrointestinal diseases. The 14-day neo-dual therapy for H pylori is considered by most countries to have good eradication rates, while the 7- and 10-day studies have been more widely explored, however, we find that their results are different. The applicability of the shorter and less expensive 10-day neo-dual therapy to our country has not yet been confirmed.

METHODS

The patients were divided into 3 groups of 200 each by randomization method. Group A: patients received vonoprazan 20 mg, bid + amoxicillin(1 g), tid, for 14 days. Group B: vonoprazan (20 mg) bid + amoxicillin (1 g) tid, duration of treatment is 10 days, group C: rabeprazole (20 mg) bid + bismuth potassium citrate tablets/tinidazole tablets/clarithromycin tablets, combined package (4.2 g), bid, duration of treatment 14 days. The main comparisons were H pylori eradication rate, adverse drug reaction profile and cost-effect ratio in each group.

RESULTS

The eradication rates of groups A, B, and C were 92.5%, 91.6%, and 80.1%, respectively. There was no significant difference in the eradication rates of groups A and B (P > .05), groups A and B had statistically significantly better eradication rates than group C (P < .05). The incidence of adverse reactions in groups A, B, and C was 9.5%, 8.5%, and 17.0%, respectively. There was no difference in the incidence of adverse reactions between A and B: (P > .05), The incidence of adverse reactions was statistically significantly lower in groups A and B than in group C (P < .05). Logistic regression analysis showed nonsmokers had a higher eradication rate (OR 2.587, 95% CI: 1.377-4.859, P = .003), and taller patients were more likely to have successful eradication (OR 1.052, 95% CI: 1.008-1.097, P = .020). Group B had the lowest cost-benefit analysis results.

CONCLUSION

Group B had an acceptable eradication rate, the lowest incidence of adverse effects, and the lowest cost analysis. Eradication is more likely to be successful in patients who do not smoke and in those who are taller.

Antibiotic Resistance, Susceptibility Testing and Stewardship in Helicobacter pylori Infection

Despite the declining trend of Helicobacter pylori (H. pylori) prevalence around the globe, ongoing efforts are still needed to optimize current and future regimens in view of the increasing antibiotic resistance. The resistance of H. pylori to different antibiotics is caused by different molecular mechanisms, and advancements in sequencing technology have come a far way in broadening our understanding and in facilitating the testing of antibiotic susceptibility to H. pylori. In this literature review, we give an overview of the molecular mechanisms behind resistance, as well as discuss and compare different antibiotic susceptibility tests based on the latest research. We also discuss the principles of antibiotic stewardship and compare the performance of empirical therapies based on up-to-date resistance patterns and susceptibility-guided therapies in providing effective H. pylori treatment. Studies and clinical guidelines should ensure that the treatment being tested or recommended can reliably achieve a pre-agreed acceptable level of eradication rate and take into account the variations in antibiotic resistance across populations. Local, regional and international organizations must work together to establish routine antibiotic susceptibility surveillance programs and enforce antibiotic stewardship in the treatment of H. pylori, so that it can be managed in a sustainable and efficient manner.

Barrett's Esophagus in Eosinophilic Esophagitis in Swiss Eosinophilic Esophagitis Cohort Study (SEECS)

INTRODUCTION

There is a complex interrelationship between gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE) potentially promoting the occurrence and modulating severity of each other reciprocally. Presence of Barrett's esophagus (BE) is a defining factor for the diagnosis of GERD. While several studies investigated the potential impact of concomitant GERD on the presentation and course of EoE, little was known with regards to BE in EoE patients.

METHODS

We analyzed prospectively collected clinical, endoscopic, and histological data from patients enrolled in the Swiss Eosinophilic Esophagitis Cohort Study (SEECS) regarding differences between EoE patients with (EoE/BE+) versus without BE (EoE/BE-) and determined the prevalence of BE in EoE patients.

RESULTS

Among a total of 509 EoE patients included in our analysis, 24 (4.7%) had concomitant BE with a high male preponderance (EoE/BE+ 83.3% vs. EoE/BE- 74.4%). While there were no differences in dysphagia, odynophagia was significantly (12.5 vs. 3.1%, p = 0.047) more common in EoE/BE+ versus EoE/BE-. General well-being at last follow-up was significantly lower in EoE/BE+. Endoscopically, we observed an increased incidence of fixed rings in the proximal esophagus in EoE/BE+ (70.8 vs. 46.3% in EoE/BE-, p = 0.019) and a higher fraction of patients with a severe fibrosis in the proximal histological specimen (8.7 vs. 1.6% in EoE/BE, p = 0.017).

CONCLUSION

Our study reveals that BE is twice as frequent in EoE patients compared to general population. Despite many similarities between EoE patients with and without BE, the finding of a more pronounced remodeling in EoE patients with Barrett is noteworthy.

Outer Membrane Vesicles (OMVs) as Biomedical Tools and Their Relevance as Immune-Modulating Agents against H. pylori Infections: Current Status and Future Prospects

Outer membrane vesicles (OMVs) are lipid-membrane-bounded nanoparticles that are released from Gram-negative bacteria via vesiculation of the outer membrane. They have vital roles in different biological processes and recently, they have received increasing attention as possible candidates for a broad variety of biomedical applications. In particular, OMVs have several characteristics that enable them to be promising candidates for immune modulation against pathogens, such as their ability to induce the host immune responses given their resemblance to the parental bacterial cell. Helicobacter pylori (H. pylori) is a common Gram-negative bacterium that infects half of the world's population and causes several gastrointestinal diseases such as peptic ulcer, gastritis, gastric lymphoma, and gastric carcinoma. The current H. pylori treatment/prevention regimens are poorly effective and have limited success. This review explores the current status and future prospects of OMVs in biomedicine with a special focus on their use as a potential candidate in immune modulation against H. pylori and its associated diseases. The emerging strategies that can be used to design OMVs as viable immunogenic candidates are discussed.

Iatrogenic factors of Helicobacter pylori eradication failure: lessons from the frontline

BACKGROUND

Iatrogenic factors play an important role in H. pylori eradication failure, whereas it can be easily missed. Therefore, we aimed to investigate and analyze these related iatrogenic factors of H. pylori eradication failure.

METHODS

A total of 508 patients who experienced H. pylori eradication failure were included in this study conducted from December 2019 to February 2022. All the patients filled out a questionnaire including demographic characteristics, duration of treatment, regimens, dosage, and time intervals in rescue treatment.

RESULTS

In the first-line treatment, 89 patients (17.5%, 89/508) used at least one antibiotic with high resistance rate in triple therapy and 57 patients (11.2%, 57/508) used two antibiotics with high resistance rates or other not recommended antibiotics in quadruple therapy. In the rescue therapy, 85 regimens were repeatedly used as salvage regimens in 58 patients (22.6%, 58/257) and 178 regimens containing antibiotics with high resistance rates were repeatedly used in 85 patients (33.1%, 85/257).

CONCLUSION

To decrease the risk of H. pylori eradication failure, iatrogenic factors need to gain more attention. Clinicians should enhance their education and training to standardize the treatment regimens, better manage the H. pylori infection, and improve the eradication rate eventually.

Association of Barrett's esophagus with Helicobacter pylori infection: a meta-analysis

Background and Aims:

Barrett’s esophagus (BE) is the only recognized precursor for esophageal adenocarcinoma. Helicobacter pylori (H. pylori) infection is a major contributing factor towards upper gastrointestinal diseases, but its relationship with BE remains controversial. Some previous studies suggested that H. pylori infection negatively correlated with BE, while others did not. This may be attributed to the difference in the selection of control groups among studies. The present meta-analysis aims to clarify their association by combining all available data from well-designed studies.

Methods:

The PubMed, EMBASE, and Cochrane Library databases were searched. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled by a random-effects model. Heterogeneity was evaluated using the Cochran’s Q test and I² statistics. Meta-regression, subgroup, and leave-one-out sensitivity analyses were employed to explore the sources of heterogeneity.

Results:

Twenty-four studies with 1,354,369 participants were included. Meta-analysis found that patients with BE had a significantly lower prevalence of H. pylori infection than those without (OR = 0.53, 95% CI = 0.45–0.64; p < 0.001). The heterogeneity was statistically significant (I² = 79%; p < 0.001). Meta-regression, subgroup, and leave-one-out sensitivity analyses did not find any source of heterogeneity. Meta-analysis of 7 studies demonstrated that CagA-positive H. pylori infection inversely correlated with BE (OR = 0.25, 95% CI = 0.15–0.44; p = 0.000), but not CagA-negative H. pylori infection (OR = 1.22, 95% CI = 0.90–1.67; p = 0.206). Meta-analysis of 4 studies also demonstrated that H. pylori infection inversely correlated with LSBE (OR = 0.39, 95% CI = 0.18–0.86; p = 0.019), but not SSBE (OR = 0.73, 95% CI = 0.30–1.77; p = 0.484).

Conclusion:

H. pylori infection negatively correlates with BE. More experimental studies should be necessary to elucidate the potential mechanisms in future.

Characteristics of gut microbiota of term small gestational age infants within 1 week and their relationship with neurodevelopment at 6 months

Introduction

Small for gestational age (SGA) infants are at a higher risk of neurodevelopmental delay than infants appropriate for gestational age (AGA). Previous studies have confirmed that gut microbiota in early life influences subsequent neurodevelopment. However, few studies have reported corresponding data in SGA populations.

Objective

We aimed to evaluate the characteristics of the gut microbiota of term SGA infants and the associations between the gut microbiota in SGA infants and neurodevelopmental outcomes at 6 months of age.

Methods

Fecal samples were collected on days 1, 3, 5, and 7 from term SGA and AGA infants born between June 2020 and June 2021 at the Peking University First Hospital. 16S ribosomal deoxyribonucleic acid amplicon sequencing was used to analyze the fecal microbiota. We followed up for 6 months and used the Ages and Stages Questionnaires-3 (ASQ-3) to evaluate the neurodevelopmental outcomes among SGA infants.

Results

A total of 162 neonates were enrolled, with 41 SGA infants (25.3%) in the study group and 121 AGA infants (74.7%) in the control group. The gut microbial diversity in the SGA group was lower than that in the AGA group on days 1, 3, 5, and 7. Non-metric multidimensional scaling and analysis of similarities showed significant differences between the two groups. The SGA group had increased relative abundances of Ralstonia (3, 5, and 7 days) and Clostridium (3 and 7 days). The dominant microorganisms of the SGA group were Ralstonia on day 1, Escherichia_Shigella on days 3 and 7, and Clostridia on day 5. We found that the gut microbial diversity of SGA infants with poor communication scores was higher than that of SGA infants with good communication scores on day 3. Fine motor scores were negatively correlated with the relative abundance of Bacteroides_fragilis on day 1. A negative correlation was observed between gross motor scores and relative abundance of Clostridium_saccharobutylicum on day 7. Bacteroidota, Bacteroidia, Bacteroides, and Bacteroides_fragilis were the dominant microorganisms in the good communication score group on day 7. Communication scores were positively correlated with the relative abundance of Bacteroidota, Bacteroides, and Bacteroides_fragilis on day 7.

Conclusion

The gut microbial diversity of term SGA infants was significantly lower in the first week of life than that of term AGA infants. Certain pathogenic and conditional pathogenic bacteria, such as Escherichia_Shigella, Ralstonia and Clostridium increased or formed the dominant microbiota in SGA infants. Alpha diversity, Bacteroidota, Bacteroides, Bacteroides_fragilis, and Clostridium_saccharobutylicum found in SGA infants may be associated with neurodevelopmental outcomes at 6 months of age, indicating possible therapeutic targets for clinical intervention.

Did an introduction of CONSORT for abstracts guidelines improve reporting quality of randomised controlled trials' abstracts on Helicobacter pylori infection? Observational study

OBJECTIVE

To determine abstracts' adherence to the Consolidated Standards of Reporting Trials for Abstracts (CONSORT-A) statement and to explore the factors associated with reporting quality.

DESIGN

An observational study.

SETTING

Abstracts of randomised controlled trials published between 2010 and 2019, found searching the MEDLINE database.

PARTICIPANTS

A total of 451 abstracts of the clinical trials on Helicobacter pylori infections were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

Abstracts' reporting quality was determined by assessing their adherence to 17-item CONSORT-A checklist, with overall score being calculated as the sum of items that were adequately reported for each abstract. Additional factors that might influence the reporting quality of the abstracts were analysed, with univariate and multivariate linear regression used to determine how those factors influenced the overall reporting quality.

RESULTS

Included abstracts had an overall median quality score of 8/17 (IQR 7-9). Large proportions of abstracts adequately reported interventions, participants, objectives, numbers randomised and conclusions (97.1, 99.3, 89.1. 94.7 and 98.4% of abstracts, respectively). Trial design, randomisation, blinding and funding were severely under-reported with only 8.0, 2.7, 11.0 and 2.0% of abstracts reporting each item. Overall quality scores for H. pylori abstracts were higher in association with CONSORT-A endorsement (B=5.698; 95% CI 1.781 to 9.615), pharmacological interventions (B=4.063; 95% CI 0.224 to 7.902), multicentre settings (B=5.057; 95% CI 2.370 to 7.743), higher numbers of participants (B=3.607; 95% CI 1.272 to 5.942), hospital settings (B=4.827; 95% CI 1.753 to 7.901) and longer abstracts (B=3.878; 95% CI 0.787 to 6.969 for abstracts with 251-300 words and B=7.404; 95% CI 3.930 to 10.878 for abstracts with more than 300 words).

CONCLUSIONS

The overall reporting quality of abstracts was inadequate. The endorsement of CONSORT-A guidelines by more journals might improve the standards of reporting.

A novel Filobacterium sp can cause chronic bronchitis in cats

Background

Cilia-associated respiratory bacillus (CARB; now known as Filobacterium rodentium gen. nov., sp. nov.) is a primary pathogen of rodents. A CARB-like organism was reported in post-mortem lung samples of cats using light and electron microscopy. Here we explore by molecular procedures if a Filobacterium sp. is a part of the normal feline lower respiratory microbiome and whether it could in some cats contribute to the development of chronic bronchial disease.

Methodology

A Filobacterium sp. was identified in three Czech cats clinically diagnosed as having chronic neutrophilic bronchitis. Bronchoalveolar lavage fluid (BALF) specimens obtained from these cats were subjected to panbacterial 16S rDNA PCR followed by Sanger sequencing of the V5 to V8 region. After these cats were treated with specific antimicrobials, their clinical signs resolved promptly, without recurrence. Next, BALF specimens from 13 Australian and 11 Italian cats with lower respiratory disease and an additional 16 lung samples of Italian cats who died of various causes were examined using next generation sequencing (NGS). Subsequently, a Filobacterium-specific qPCR assay was developed and used to re-test BALF specimens from the 11 Italian cats and lung tissue homogenates from the additional 16 deceased cats.

Principal findings

An amplicon of 548 bp with 91.24% sequence agreement with Filobacterium rodentium was obtained from all three patients, suggesting the novel Filobacterium sp. was the cause of their lower respiratory disease. The novel Filobacterium sp., which we propose to call F. felis, was detected in 3/3 Czech cats with chronic neutrophilic bronchitis, 13/13 Australian cats and 6/11 Italian cats with chronic lower respiratory disease, and 14/16 necropsy lung specimens from Italian cats. NGS and qPCR results all showed identical sequences. The Filobacterium sp. was sometimes the preponderant bacterial species in BALF specimens from cats with lower airway disease. There was an association between the presence of large numbers (greater than 10⁵ organisms/mL) of Filobacterium and the presence of neutrophilic and/or histiocytic inflammation, although only a subset of inflammatory BALF specimens had F. felis as the preponderant organism.

Conclusion

The novel Filobacterium sp. comprises a finite part of the normal feline lower respiratory microbiome. Under certain circumstances it can increase in absolute and relative abundance and give rise to neutrophilic and/or histiocytic bronchitis, bronchiolitis and bronchopneumonia. These findings strongly suggest that F. felis could be an underdiagnosed cause of feline bronchial disease.

Changes in the Seroprevalence of Helicobacter pylori among the Lithuanian Medical Students over the Last 25 Years and Its Relation to Dyspeptic Symptoms

Background and Objectives: The prevalence of Helicobacter pylori infection is decreasing in the Western world, while remaining high in developing countries. There is limited up-to-date information about the prevalence of H. pylori in Central and Eastern Europe. The aim of our study was to assess the seroprevalence of H. pylori and its trend over the past 25 years among students of the Lithuanian University of Health Sciences (LUHS) and to assess its relation to dyspeptic symptoms. Materials and Methods: In the years 1995, 2012, 2016 and 2020, students from Medical and Nursing Faculties of LUHS were tested for the presence of antibodies against H. pylori by performing serological tests from finger capillary blood. In addition, in the years 2012, 2016 and 2020, the students completed a gastrointestinal symptom rating scale (GSRS) questionnaire in order to assess dyspeptic symptoms. The study population consisted of 120 students in the year 1995 (mean age—21.3 ± 1.0 years), 187 students in the year 2012 (mean age—22.4 ± 0.7 years), 262 students in the year 2016 (mean age—20.4 ± 1.0 years) and 148 students in the year 2020 (mean age—20.4 ± 1.7 years). Results: The seroprevalence for H. pylori was positive in 62 (51.7%) students in 1995, in 57 (30.4%) students in 2012, in 69 (26.3%) students in 2016 and in 21 (14.2%) students in 2020. The statistically significant difference was found between all study years, except between 2012 and 2016. There were no significant differences in frequency and intensity of upper dyspeptic symptoms between H. pylori positive and negative students. Conclusions: Over the last 25 years the seroprevalence of H. pylori among students of LUHS has decreased significantly. No consistent differences in dyspeptic symptoms among H. pylori positive and negative subgroups were found.

Current status of Helicobacter pylori eradication and risk factors for eradication failure

BACKGROUND

The Helicobacter pylori (H. pylori) eradication rate is decreasing in the general population of China.

AIM

To evaluate the H. pylori eradication status in real-world clinical practice and to explore factors related to eradication failure.

METHODS

Patients with H. pylori infection who were treated with standard 14-d quadruple therapy and received a test of cure at a provincial medical institution between June 2018 and May 2019 were enrolled. Demographic and clinical data were recorded. Eradication rates were calculated and compared between regimens and subgroups. Multivariate analysis was performed to identify predictors of eradication failure.

RESULTS

Of 2610 patients enrolled, eradication was successful in 1999 (76.6%) patients. Amoxicillin-containing quadruple regimens showed a higher eradication rate than other quadruple therapy regimens (83.0% vs 69.0%, P < 0.001). The quadruple therapy containing amoxicillin plus clarithromycin achieved the highest eradication rate (83.5%). Primary therapy had a higher eradication rate than rescue therapy (78.3% vs 66.5%, P < 0.001). In rescue therapy, the amoxicillin- and furazolidone-containing regimens achieved the highest eradication rate (80.8%). Esomeprazole-containing regimens showed a higher eradication rate than those containing other proton pump inhibitors (81.8% vs 74.9%, P = 0.001). Multivariate regression analysis found that older age, prior therapy, and use of omeprazole or pantoprazole were associated with an increased risk of eradication failure.

CONCLUSION

The total eradication rate is 76.6%. Amoxicillin-containing regimens are superior to other regimens. Age, prior therapy, and use of omeprazole or pantoprazole are independent risk factors for eradication failure.

Treatment of Helicobacter pylori infection: a clinical practice update

Helicobacter pylori infection still represents a major health issue, especially in developing countries, with an estimate of 4 billion of infected subjects in 2015. The increase of antibiotic resistance has undermined the efficacy of standard triple therapy leading to more complex regimens. This review summarizes recommendations of international guidelines and reports the most recent evidence from meta-analyses and clinical trials on the treatment of Helicobacter pylori infection. The choice of H. pylori eradication regimen should be based on the local prevalence of clarithromycin resistance and the previous use of macrolides. Quadruple therapies (bismuth quadruple and concomitant) are the recommended regimens for the first-line treatment; a 14-day clarithromycin-containing triple therapy is suggested in areas with low prevalence of clarithromycin resistance and in patients without previous use of macrolides. Data on the efficacy of sequential therapy against clarithromycin resistant H. pylori strains are contradictory, and its use in the treatment of H. pylori infection is generally discouraged. Second-line treatments include levofloxacin-containing triple therapy and bismuth quadruple therapy. Probiotic supplementation should be used with the aim to reduce antibiotic-related adverse events. Recent evidence would support current guideline recommendations for the treatment of Helicobacter pylori infection.

Risk of stomach cancer incidence in a cohort of Mayak PA workers occupationally exposed to ionizing radiation

Stomach cancer is a widespread health condition associated with environmental and genetic factors. Contribution of ionizing radiation to stomach cancer etiology is not sufficiently studied. This study was aimed to assess an association of the stomach cancer incidence risk with doses from occupational radiation exposure in a cohort of workers hired at main Mayak production association facilities in 1948–1982 taking into account non-radiation factors including digestive disorders. The study cohort comprised 22,377 individuals and by 31.12.2013 343 stomach cancer diagnoses had been reported among the cohort members. Occupational stomach absorbed doses were provided by the Mayak Worker Dosimetry System– 2008 (MWDS–2008) for external gamma ray exposure and by the Mayak Worker Dosimetry System– 2013 (MWDS–2013) for internal exposure to plutonium. Excess relative risks (ERR) per Gy for stomach cancer were estimated using the Poisson’s regression. Analyses were run using the AMFIT module of the EPICURE software. The stomach cancer incidence risk in the study cohort was found to be significantly associated with the stomach absorbed dose of gamma rays: ERR/Gy = 0.19 (95% CI: 0.01, 0.44) with a 0 year lag, and ERR/Gy = 0.20 (95% CI: 0.01, 0.45) with a 5 year lag. To estimate the baseline risk, sex, attained age, smoking status and alcohol consumption, chronic diseases (peptic ulcer, gastritis and duodenitis) were taken into account. No modifications of the radiogenic risk by non-radiation factors were found in the study worker cohort. No association of the stomach cancer incidence risk with internal exposure to incorporated plutonium was observed.