IntroductionPopulation-based eradication of Helicobacter pylori has been suggested to be cost-effective and is recommended by international guidelines. However, the potential adverse effects of widespread antibiotic use that this would entail have not been sufficiently studied. An alternative way to decrease gastric cancer mortality is by non-invasive search for precancerous lesions, in particular gastric atrophy; pepsinogen tests are the best currently available alternative. The primary objective of GISTAR is to determine whether H pylori eradication combined with pepsinogen testing reduces mortality from gastric cancer among 40–64-year-old individuals. The secondary objectives include evaluation of H pylori eradication effectiveness in gastric cancer prevention in patients with precancerous lesions and evaluation of the potential adverse events, including effects on microbiome.Methods and analysisIndividuals are recruited from general population (50% men) in areas with high gastric cancer risk in Europe and undergo detailed lifestyle and medical history questionnaire before being randomly allocated to intervention or control groups. The intervention group undergoes H pylori testing and is offered eradication therapy if positive; in addition, pepsinogen levels are detected in plasma and those with decreased levels are referred for upper endoscopy. All participants are offered faecal occult blood testing as an incentive for study participation. Effectiveness of eradication and the spectrum of adverse events are evaluated in study subpopulations. A 35% difference in gastric cancer mortality between the groups is expected to be detectable at 90% power after 15 years if 30 000 individuals are recruited. Biological materials are biobanked for the main and ancillary studies. The study procedure and assumptions will be tested during the pilot phase.Ethics and disseminationThe study was approved by the respective ethics committees. An independent Data Safety and Monitoring Board has been established. The findings will be published in peer-reviewed journals and presented at scientific meetings.Trial registration numberNCT02047994

Background: Detection of diseases via exhaled breath remains an attractive idea despite persisting gaps in understanding the origin of volatile organic compounds (VOCs) and their relationship with the disease of interest. Data on factors potentially influencing the results of breath analysis remain rather sparse and often controversial. In this study, we aimed to investigate the associations of common VOCs in exhaled breath of average-risk individuals with socio-demographic and lifestyle factors, medical conditions as well as diet. Methods: Alveolar breath samples of 1447 men and women were collected in the morning after fasting and were analyzed using gas-chromatography linked with mass-spectrometry. Study participants were 40–64 years old, cancer-free, with overall good health status. The associations between selected VOCs and various factors determined from the questionnaire data were assessed using two-part-Wilcoxon test and Jonckheere–Terpstra trend test. Results: Fifteen VOCs where each of them was detected in at least 80% of the study population were included in this analysis. Statistically significant associations with various VOCs were demonstrated for gender and consumption of certain foods, such as coffee, leeks and garlic, while smoking was not associated with any of the analyzed compounds. Conclusion: Factors potentially modifying the composition of exhaled breath, such as dietary factors, deserve careful attention in the design and analysis of studies accessing the use of VOCs as diagnostic markers.

Background The aim was to derive a breath‐based classifier for gastric cancer using a nanomaterial‐based sensor array, and to validate it in a large screening population. Methods A new training algorithm for the diagnosis of gastric cancer was derived from previous breath samples from patients with gastric cancer and healthy controls in a clinical setting, and validated in a blinded manner in a screening population. Results The training algorithm was derived using breath samples from 99 patients with gastric cancer and 342 healthy controls, and validated in a population of 726 people. The calculated training set algorithm had 82 per cent sensitivity, 78 per cent specificity and 79 per cent accuracy. The algorithm correctly classified all three patients with gastric cancer and 570 of the 723 cancer‐free controls in the screening population, yielding 100 per cent sensitivity, 79 per cent specificity and 79 per cent accuracy. Further analyses of lifestyle and confounding factors were not associated with the classifier. Conclusion This first validation of a nanomaterial sensor array‐based algorithm for gastric cancer detection from breath samples in a large screening population supports the potential of this technology for the early detection of gastric cancer.

Background and Aims: The prevalence of Helicobacter pylori (H. pylori) infection is higher in developing countries and is often linked to lower socioeconomic status. Few studies have investigated the association between H. pylori and individual level characteristics in Europe, where several countries have a high prevalence of H. pylori infection. The study aimed to identify risk factors for H. pylori infection among adults in a large clinical trial in Latvia. Methods: 1,855 participants (40-64 years) of the “Multicenter randomized study of H. pylori eradication and pepsinogen testing for prevention of gastric cancer mortality” (GISTAR study) in Latvia tested for H. pylori IgG antibodies were included in a cross-sectional analysis. Sociodemographic, lifestyle and medical factors were compared for participants seropositive (H. pylori+) and seronegative. Mutually adjusted odds ratios (OR) were calculated for H. pylori+ and factors significant in univariate analysis (education, smoking, binge drinking, several dietary habits, history of H. pylori eradication and disease), adjusting for age, gender and income. Results: Of the participants 1,044 (55.4%) were H. pylori seropositive. The infection was associated with current (OR: 1.34, 95%CI: 1.01-1.78) and former (OR: 1.38; 95%CI: 1.03-1.85) smoking, binge drinking (OR: 1.35; 95%CI: 1.03-1.78), having ≥200g dairy daily (OR: 1.37; 95%CI: 1.11-1.69), and very hot food/drinks (OR: 1.32; 95%CI: 1.03-1.69) and inversely with ≥400g vegetables/fruit daily (OR: 0.76; 95%CI: 0.60-0.96), history of H. pylori eradication (OR: 0.57; 95%CI: 0.39-0.84), peptic ulcer (OR: 0.55; 95%CI: 0.38-0.80) and cardiovascular disease (OR: 0.78; 95%CI: 0.61-0.99). Conclusions: After mutual adjustment, H. pylori seropositivity was associated with lifestyle and in particular dietary factors rather than socioeconomic indicators in contrast to the majority of other studies.