Helicobacter pylori risk associated with childhood home environment

Epidemiological Characteristics of Helicobacter pylori Infection in Children in Northeast Romania

(1) Background: Although gastritis has been associated with multiple etiologies, in pediatrics the main etiology is idiopathic. Many studies have reported mild-to-severe gastritis Helicobacter pylori (H. pylori) as an etiological factor. We evaluated the distribution of the infection with H. pylori by age, gender and place of living; (2) Methods: A retrospective study was conducted over a period of 3 years, over a cohort of 1757 patients of both sexes, aged between 1 and 18 years, admitted to a regional gastroenterology center in Iasi, Romania, with clinical signs of gastritis which underwent upper gastrointestinal endoscopy. The research was based on the analysis of data from patient observation charts and hospital discharge tickets, as well as endoscopy result registers; (3) Results: Out of the 1757 children, in 30.8% of cases the H. pylori infection was present. Out of them, 26.8% were males and 73.2% females. The average age of children with an H. pylori infection was higher (14.1 + 2.8 DS), compared with children without H. pylori (12.8 + 3.7 SD), an average difference of 1.3 years (95% confidence interval 0.96 to 1.66; p < 0.001). By place of living, children with H. pylori infection were from urban areas at 24.7% and from rural areas at 75.3%; (4) Conclusions: H. pylori infection incidence is still high in children, especially in teenagers, so extensive prevention and treatment programs are needed.

Changes in prevalence of Helicobacter pylori in Japan from 2008 to 2018: a repeated cross-sectional study

OBJECTIVES

To understand the recent prevalence and time trends of Helicobacter pylori infection rates in the Japanese population.

DESIGN

Repeated cross-sectional study.

PARTICIPANTS

A total of 22 120 workers (age: 35-65 years) from one Japanese company, who underwent serum H. pylori antibody tests in a health check-up between 2008 and 2018.

MEASURES

H. pylori infection rates among participants aged 35 years from 2008 to 2018, and participants aged 35, 40, 45, and 50-65 years in 2018, based on the results of serum antibody tests, were analysed. In the 2018 analysis, in addition to the antibody test results, all participants who had undergone eradication treatment for H. pylori were considered as infected. Trends were examined using joinpoint analysis.

RESULTS

H. pylori was detected in 1100 of 7586 male and 190 of 1739 female participants aged 35 years. Annual infection rates among those aged 35 years showed linear downward trends as follows: men, 17.5% in 2008 to 10.1% in 2018 (slope: -0.66); women, 12.3% in 2008 to 9.2% in 2018 (slope: -0.51) without joinpoints. In the 2018 analysis, 2432 of 9580 men and 431 of 1854 women were H. pylori positive. Infection rates tended to increase with older age (men: 11.0% (35 years) to 47.7% (65 years); women: 10.0% (35 years) to 40.0% (65 years)), and showed joinpoints in both sexes (men: 54 years; women: 45 years). Although both the first and second trends were upward, the second trend for both men and women was steeper than the first trend (p<0.05).

CONCLUSIONS

Our study demonstrated that in the previous 11 years, infection rates of H. pylori in 35-year-old male and female Japanese workers have constantly decreased, and furthermore, analysis of various age groups showed joinpoints around 50 years, suggesting a consistent declining trend in H. pylori infection rates in Japan.

Prevalence of Helicobacter pylori infection in the general population evaluated by a resident-register-based epidemiological study

BACKGROUND

The current status of Helicobacter pylori infection in Japan has not been investigated. We evaluated the status of H. pylori infection in a Japanese general population using large-scale resident-register-based sampling.

METHODS

All 6069 adults in a rural town and 6000 adults in two urban cities (3000 each), selected by register-based random sampling, were enrolled in our health check-up program. Antibody titers against Helicobacter pylori (cut-off value was 3 U/mL by Eiken E-plate) were evaluated, and subjects with a positive result were encouraged to undergo further examinations.

RESULTS

A total of 1586 subjects participated in serum sampling. The overall prevalence of H. pylori infection was 40.0% (634/1586), and it increased with age both in rural and urban areas. Although the overall positive rate was higher in the rural area (49.4%) than in the urban areas (35.6 and 32.3%), there was no difference in H. pylori status of younger subjects between the two areas. Among 634 patients with a positive titer, 374 (59.0%) underwent further examinations including endoscopic examination, and 180/634 (28.4%) patients received eradication therapy. Gastric neoplasms (three adenocarcinomas and one adenoma) were found in our screening program.

CONCLUSION

We clarified population-based random sampling data of H. pylori infection in a Japanese general population. In younger subjects, a decrease in the prevalence of H. pylori infection was confirmed both in rural and urban areas. This provides basic information for establishing a strategy to reduce gastric cancer deaths.

Helicobacter pylori (H. pylori) risk factor analysis and prevalence prediction: a machine learning-based approach

Background

Although previous epidemiological studies have examined the potential risk factors that increase the likelihood of acquiring Helicobacter pylori infections, most of these analyses have utilized conventional statistical models, including logistic regression, and have not benefited from advanced machine learning techniques.

Objective

We examined H. pylori infection risk factors among school children using machine learning algorithms to identify important risk factors as well as to determine whether machine learning can be used to predict H. pylori infection status.

Methods

We applied feature selection and classification algorithms to data from a school-based cross-sectional survey in Ethiopia. The data set included 954 school children with 27 sociodemographic and lifestyle variables. We conducted five runs of tenfold cross-validation on the data. We combined the results of these runs for each combination of feature selection (e.g., Information Gain) and classification (e.g., Support Vector Machines) algorithms.

Results

The XGBoost classifier had the highest accuracy in predicting H. pylori infection status with an accuracy of 77%—a 13% improvement from the baseline accuracy of guessing the most frequent class (64% of the samples were H. Pylori negative.) K-Nearest Neighbors showed the worst performance across all classifiers. A similar performance was observed using the F1-score and area under the receiver operating curve (AUROC) classifier evaluation metrics. Among all features, place of residence (with urban residence increasing risk) was the most common risk factor for H. pylori infection, regardless of the feature selection method choice. Additionally, our machine learning algorithms identified other important risk factors for H. pylori infection, such as; electricity usage in the home, toilet type, and waste disposal location. Using a 75% cutoff for robustness, machine learning identified five of the eight significant features found by traditional multivariate logistic regression. However, when a lower robustness threshold is used, machine learning approaches identified more H. pylori risk factors than multivariate logistic regression and suggested risk factors not detected by logistic regression.

Conclusion

This study provides evidence that machine learning approaches are positioned to uncover H. pylori infection risk factors and predict H. pylori infection status. These approaches identify similar risk factors and predict infection with comparable accuracy to logistic regression, thus they could be used as an alternative method.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07625-7.

Impact of socioeconomic status and sibling number on the prevalence of Helicobacter pylori infection: a cross-sectional study in a Japanese population

Helicobacter pylori infection is a significant risk factor for gastric cancer. The infection is acquired mainly in early childhood and is influenced by environmental factors, including socioeconomic status and sibling number. However, the impact of socioeconomic status and sibling number on Helicobacter pylori infection has not been well studied in Japan. We conducted a cross-sectional study to evaluate the impact of socioeconomic status, represented by education level, and sibling number on the prevalence of Helicobacter pylori infection among 3,423 non-cancer subjects who visited Aichi Cancer Center between 2005 and 2013. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using a logistic regression model adjusted for potential confounding variables. Of the 3,423 subjects, 1,459 (42.6%) were Helicobacter pylori-positive. The prevalence of Helicobacter pylori infection linearly decreased with increasing socioeconomic status [ORs (95% CIs) of moderate and high socioeconomic status relative to low socioeconomic status of 0.67 (0.53-0.84) and 0.43 (0.34-0.54), respectively; P trend=9.7×10^-17]. In contrast, the prevalence of Helicobacter pylori infection linearly increased with increasing sibling number [ORs (95% CIs) of SN 3-4 and ≥5 relative to sibling number ≤2 of 1.74 (1.47-2.06) and 2.54 (2.12-3.04), respectively; P trend=1.2×10^-24]. This study showed that socioeconomic status and sibling number were significantly associated with the prevalence of Helicobacter pylori infection.

Individual and household correlates of Helicobacter pylori infection among Young Ethiopian children in Ziway, Central Ethiopia

Background

Investigating distinct individual- and household-level risk factors for acquiring Helicobacter pylori (H. pylori) infection can inform disease prevention efforts and implicate possible routes of transmission. This study determined the magnitude of H. pylori infection among schoolchildren in Ziway, central Ethiopia and identified personal and household correlates of H. pylori infection in young Ethiopian children.

Methods

A total of 434 schoolchildren participated in this cross-sectional study. Infection status was assessed using antigen and antibody rapid tests. Demographic and lifestyle information was obtained from parents via an interviewer-led questionnaire. Univariate and multivariate logistic regressions were performed to assess the relationships between potential individual- and household-level risk factors and H. pylori infection.

Results

The prevalence of H. pylori infection was 65.7% (285/434). Of the personal variables assessed, the age group 10–14 years was found to be significantly associated with higher odds of H. pylori infection in univariate analysis (COR = 2.22, 95% CI: 1.06–4.66, p = 0.03) and remained positively correlated after adjusting for confounding factors. Of the household-level factors explored, having a traditional pit or no toilet was found to be significantly associated with 3.93-fold higher odds of H. pylori infection (AOR = 3.93, 95% CI: 1.51–10.3, p = 0.01), while the presence of smokers in the household was associated with 68% lower odds of infection (AOR = 0.32, 95% CI: 0.11–0.89, p = 0.03).

Conclusion

This study from a developing country provides additional evidence for older age as a personal risk factor for H. pylori infection and identifies correlations between socioeconomic and sanitation household factors and positive childhood infection status. The associations reported here support the hypothesized fecal-oralroute of transmission for H. pylori.

Guidelines for the management of Helicobacter pylori infection in Japan: 2016 Revised Edition

BACKGROUND

Since "Helicobacter pylori (H. pylori) infection" was set as the indication in the Japanese Society for Helicobacter Research (JSHR) Guidelines 2009, eradication treatment for H. pylori gastritis is covered under insurance since 2013 in Japan, and the number of H. pylori eradication has rapidly increased. Under such circumstances, JSHR has made the third revision to the "Guidelines for diagnosis and treatment of H. pylori infection" for the first time in 7 years.

METHODS

The Guideline Committee held 10 meetings. Articles published between the establishment of the 2009 Guidelines and March 2016 were reviewed and classified according to the evidence level; the statements were revised on the basis of this review. After inviting public comments, the revised statements were finalized using the Delphi method.

RESULTS

There was no change in the basic policy that H. pylori infectious disease is an indication for eradication. Other diseases presumed to be associated with H. pylori infection were added as indications. Serum pepsinogen level, endoscopic examination, and X-ray examination were added to the diagnostic methods. The effects of 1-week triple therapy consisting of potassium-competitive acid blocker (P-CAB), amoxicillin, and clarithromycin have improved, and high eradication rates can also be expected with proton pump inhibitors (PPI) or P-CAB combined with amoxicillin and metronidazole. If the susceptibility test is not performed, the triple PPI or P-CAB/amoxicillin/metronidazole therapy should be chosen, because the PPI/amoxicillin/metronidazole combination demonstrated a significantly higher eradication rate than PPI/amoxicillin/clarithromycin. In the proposal for gastric cancer prevention, we divided gastric cancer prevention measures by age from adolescent to elderly, who are at an increased gastric cancer risk, and presented measures for gastric cancer prevention primarily based on H. pylori eradication.

CONCLUSION

We expect the revised guidelines to facilitate appropriate interventions for patients with H. pylori infection and accomplish its eradication and prevention of gastric cancer.

Prevalence of Helicobacter pylori among Alaskans: Factors associated with infection and comparison of urea breath test and anti-Helicobacter pylori IgG antibodies

BACKGROUND

Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti- H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection.

METHODS

A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti- H. pylori IgG antibodies; a UBT was administered to participants > 5 years old.

RESULTS

We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti- H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age ≥ 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered.

CONCLUSIONS

Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity.

Family history of gastric mucosal abnormality and the risk of gastric cancer: a population-based observational study

Background

An increased prevalence of gastric premalignant abnormalities was reported among relatives of gastric cancer (GC) patients, with rather unexplored clinical significance.

Methods

In Swedish computerized pathology registers, we identified, as 'index' persons, 232 681 patients who were born after 1931 and underwent endoscopic examination with stomach biopsy between 1979 and 2014. Through linkage with the Multi-Generation Register, we compiled a cohort consisting of 903 337 first-degree relatives of these biopsied patients. The relatives were grouped according to their 'family histories', defined as the first gastric mucosal diagnosis of the index person or GC family history known before that. Standardized incidence ratios (SIRs) provided comparisons with the matched general population. For internal comparisons with relatives with 'normal/minor changes' mucosal family history, hazard ratios (HRs) were derived from adjusted Cox regression modelling.

Results

During follow-up, 1302 relatives developed GC. Crude incidence rates of non-cardia GC were 7.7 × 10-5 year-1 for the 'normal/minor changes' family history group (SIR = 1.0), 11.2 to 12.6 × 10-5 year-1 for precancerous changes groups (atrophic gastritis/intestinal metaplasia/dysplasia, SIR = 1.5 to 1.6), and 18.4 × 10-5 year-1 for those with a family history of GC (SIR = 2.3). HRs derived from Cox models corroborated the family history-related risk pattern, with the most conspicuous trend observed among siblings-a family history of any precancerous changes and GC was associated with, respectively, a 2.5-fold and a 3.8-fold increment in non-cardia GC hazard, compared with siblings of index persons with 'normal/minor mucosal changes'.

Conclusions

The precancerous mucosal abnormalities recorded in a person's first-degree relatives may improve GC risk stratification for this person.

Impact of health insurance coverage for Helicobacter pylori gastritis on the trends in eradication therapy in Japan: retrospective observational study and simulation study based on real-world data

OBJECTIVES

To explore the prevalence of Helicobacter pylori infection in Japan and the trends of its eradication therapy before and after the changes of the insurance coverage policy, first started in 2000, and expanded to cover H. pylori-positive gastritis in 2013. The impacts that the changes brought were estimated.

METHODS

In this retrospective observational study and simulation study based on health insurance claims data, product sales data and relevant studies, individuals who received triple therapy (amoxicillin, clarithromycin, proton-pump inhibitors or potassium-competitive acid blockers) were defined as the first-time patients for H. pylori eradication in two Japanese health insurance claims databases (from approximately 1.6 million and 10.5 million individuals). Each sales data of eradication packages and examination kits were used to estimate the number of H. pylori-eradicated individuals nationwide. The prevalence of H. pylori infection, including the future rate, was predicted using previous studies and the estimated population trend by a national institute. Cases completed prior to the policy change on insurance coverage were simulated to estimate what would have happened had there been no change in the policy.

RESULTS

The numbers of patients first received eradication therapy were 81 119 and 170 993 from two databases. The nationwide estimated number of patients successfully eradicated was approximately 650 000 per year between 2001 and 2012, whereas it rapidly rose to 1 380-000 per year in 2013. The estimated prevalence of infection in 2050 is 5%, this rate was estimated to be 28% and 22% if the policy changes had not occurred in 2000 and 2013, respectively.

CONCLUSIONS

The impact of policy changes for H. pylori eradication therapy on the prevalence of infection was shown. The results suggest that insurance coverage expansion may also reduce the prevalence in other countries with a high prevalence of H. pylori infection if the reinfection is low.

Helicobacter, Hygiene, Atopy, and Asthma

The hygiene hypothesis links environmental and microbial exposures in early life to the prevalence of atopy, allergy, and asthma. Helicobacter pylori infection is typically acquired in childhood and acquisition of the infection is associated with poor household hygiene. Some population surveys have shown an inverse association between H. pylori infection and atopy, allergy, and asthma leading to the suggestion that H. pylori infection may be protective against disease; others consider it simply a biomarker for poor household hygiene. We review the relevant surveys, cohort studies, meta-analyses, and studies testing the protective hypothesis. Overall, the results of surveys and cohort studies are inconsistent, whereas meta-analyses show a significant but weak inverse correlation. In contrast, studies directly testing the protection hypothesis in relation to asthma in populations with poor hygiene and low H. pylori prevalence failed to confirm a protective effect. H. pylori is a major cause of human disease including chronic gastritis, peptic ulcer, and gastric malignancies. H. pylori infections most likely serve as a biomarker for poor hygienic conditions in childhood. We conclude that while synergistic interactions between environmental factors in childhood are important determinants of the pathogenesis of atopy, allergy, and asthma; H. pylori is inversely related to good hygiene and thus it's presence serves as a biomarker rather than for a specific prevention role for H. pylori or H. pylori antigens.

Contemporary migration patterns in the prevalence of Helicobacter pylori infection: A systematic review

BACKGROUND

A rapid growth in the number of international migrants over the past years has occurred with most traveling to more affluent settings. As Helicobacter pylori infects over half of the adult population and its prevalence is higher in developing countries, understanding the prevalence of infection in migrants can provide insight into future trends in the burden and management of infection. We aimed to describe the prevalence of H. pylori among migrants through a systematic literature review.

METHODS

We searched PubMed^® from inception to September 2015 to identify studies reporting the prevalence of H. pylori in international migrants according to country of birth for first-generation, and country of birth and parents' nationality for successive generations. Comparable data from origin and destination populations were obtained from the same studies or, when not present, from a previous systematic review on H. pylori worldwide.

RESULTS

A total of 28 eligible studies were identified with data for 29 origin and 12 destination countries. Two studies that evaluated refugees presented prevalences of infection higher than both the origin and destination countries. Otherwise, the prevalences among migrants were generally similar or below that of the origin and higher than the destination. Second- or more generation had lower prevalences compared to first-generation migrants.

CONCLUSIONS

Our study findings are consistent with what would be expected based on the prevalence of H. pylori worldwide. The results of this review show that migrants are particularly at risk of infection and help to identify gaps in the knowledge of migrants' prevalence of infection globally.

Declining trends in prevalence of Helicobacter pylori infection by birth-year in a Japanese population

Gastric cancer incidence and mortality have been decreasing in Japan. These decreases are likely due to a decrease in prevalence of Helicobacter pylori infection. Our aim was to characterize the trends in prevalence of H. pylori infection focused on birth-year. We carried out a cross-sectional study that included 4285 subjects who were born from 1926 to 1989. We defined H. pylori infection by the serum H. pylori antibody titer. Individuals having H. pylori infection and those with negative H. pylori antibody titer and positive pepsinogen test were defined as high-risk individuals for gastric cancer. We estimated the birth-year percent change (BPC) of the prevalence by Joinpoint regression analysis. The prevalence of H. pylori infection among the subjects born from 1927 to 1949 decreased from 54.0% to 42.0% with a BPC of -1.2%. It was followed by a rapid decline in those born between 1949 (42.0%) and 1961 (24.0%) with a BPC of -4.5%, which was followed by those born between 1961 (24.0%) and 1988 (14.0%) with a BPC of -2.1%. The proportion of high-risk individuals for gastric cancer among the subjects born from 1927 to 1942 decreased from 62.0% to 55.0% with a BPC of -0.8%. A subsequent rapid declining trend was observed in those born between 1942 (55.0%) and 1972 (18.0%) with a BPC of -3.6%, and then it became stable. These remarkable declining trends in the prevalence of H. pylori infection by birth-year would be useful to predict the future trend in gastric cancer incidence in Japan.

Risk of gastric cancer by water source: evidence from the Golestan case-control study

Background

Gastric cancer (GC) is the world’s fifth most common cancer, and the third leading cause of cancer-related death. Over 70% of incident cases and deaths occur in developing countries. We explored whether disparities in access to improved drinking water sources were associated with GC risk in the Golestan Gastric Cancer Case Control Study.

Methods and Findings

306 cases and 605 controls were matched on age, gender, and place of residence. We conducted unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CI), adjusted for age, gender, ethnicity, marital status, education, head of household education, place of birth and residence, homeownership, home size, wealth score, vegetable consumption, and H. pylori seropositivity. Fully-adjusted ORs were 0.23 (95% CI: 0.05–1.04) for chlorinated well water, 4.58 (95% CI: 2.07–10.16) for unchlorinated well water, 4.26 (95% CI: 1.81–10.04) for surface water, 1.11 (95% CI: 0.61–2.03) for water from cisterns, and 1.79 (95% CI: 1.20–2.69) for all unpiped sources, compared to in-home piped water. Comparing unchlorinated water to chlorinated water, we found over a two-fold increased GC risk (OR 2.37, 95% CI: 1.56–3.61).

Conclusions

Unpiped and unchlorinated drinking water sources, particularly wells and surface water, were significantly associated with the risk of GC.

Low prevalence and incidence of Helicobacter pylori infection in children: a population-based study in Japan

BACKGROUND

Infection of Helicobacter pylori mainly occurs in childhood. In Japan, incidence of gastric cancer is still high in the senior citizen population, but little is known about the current H. pylori infection status among children or their family members.

METHODS

As a population-based study, the prevalence of H. pylori infection and change in infection status over a 1-year interval in children were determined. Family members of some participants were also invited to participate in the study to determine their infection status. All children of specific ages attending 16 schools in Sasayama, Hyogo Prefecture, were invited to participate. H. pylori infection was determined by the stool antigen test and diagnosis confirmed by polymerase chain reaction and the urea breath test.

RESULTS

Helicobacter pylori prevalence was 1.9% among 689 children aged 0-8 years in 2010 and 1.8% among 835 children aged 0-11 in 2011. No feco-conversion was observed in 430 children aged 0-8 years (170 were aged 0-4 years) who provided follow-up stool samples after 1 year. The prevalence of infection was 6% (2 of 33) and 38% (6 of 16) in mothers of negative and positive probands (p = .04), respectively, and 12% (3 of 25) and 50% (8 of 16) (p = .01), respectively, in fathers.

CONCLUSION

Helicobacter pylori prevalence in Japanese children is approximately 1.8%, which is much lower than that reported in Japanese adults. New infection may be rare. Parent-to-child infection is thought to be the main infection route of the infrequent infection for children in Japan.

Immunology and vaccines and nanovaccines for Helicobacter pylori infection

Helicobacter pylori infection is very common worldwide and is an important cause of gastritis, peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma. Since the eradication requires treatment with multidrug regimens, prevention of primary infection by a suitable vaccine is attractive. Developing vaccines on the spot when and where an infection is breaking out might be possible, thanks to engineered nanoparticles. In this review, the nature of the host immune response to H. pylori infection is considered. We explain recent candidate vaccines and prophylactic or therapeutic immunization strategies for use against H. pylori. We also describe identification of different types of immune responses that may be related to protection against H. pylori infection. Thus, it seems that there is still a strong need to clarify the main protective immune response against H. pylori.

Breast-feeding and Helicobacter pylori infection: systematic review and meta-analysis

Objective

To quantify the association between breast-feeding and Helicobacter pylori infection, among children and adolescents.

Design

We searched MEDLINETM and ScopusTM up to January 2013. Summary relative risk estimates (RR) and 95 % confidence intervals were computed through the DerSimonian and Laird method. Heterogeneity was quantified using the I2 statistic.

Setting

Twenty-seven countries/regions; four low-income, thirteen middle-income and ten high-income countries/regions.

Subjects

Studies involving samples of children and adolescents, aged 0 to 19 years.

Results

We identified thirty-eight eligible studies, which is nearly twice the number included in a previous meta-analysis on this topic. Fifteen studies compared ever v. never breast-fed subjects; the summary RR was 0·87 (95 % CI 0·57, 1·32; I2=34·4 %) in middle-income and 0·85 (95 % CI 0·54, 1·34; I2=79·1 %) in high-income settings. The effect of breast-feeding for ≥4–6 months was assessed in ten studies from middle-income (summary RR=0·66; 95 % CI 0·44, 0·98; I2=65·7 %) and two from high-income countries (summary RR=1·56; 95 % CI 0·57, 4·26; I2=68·3 %). Two studies assessed the effect of exclusive breast-feeding until 6 months (OR=0·91; 95 % CI 0·61, 1·34 and OR=1·71; 95 % CI 0·66, 4·47, respectively).

Conclusions

Our results suggest a protective effect of breast-feeding in economically less developed settings. However, further research is needed, with a finer assessment of the exposure to breast-feeding and careful control for confounding, before definite conclusions can be reached.

Prevalence of Helicobacter pylori infection by birth year and geographic area in Japan

BACKGROUND

Helicobacter pylori (H. pylori)-related diseases are responsible for a tremendous amount of morbidity and mortality in Japan. We estimated the prevalence of H. pylori infection by sex, birth year, and geographic area among Japanese adults.

MATERIALS AND METHODS

This cross-sectional study included 14,716 subjects aged 20 years or more who underwent a health checkup between May 1997 and March 2013 in seven geographic areas throughout Japan. Relevant information on the demographics and status of H. pylori infection was retrieved from the electronic database. The univariate log-binominal regression model was used to estimate the prevalence of H. pylori infection, taking birth year into consideration. The multivariate log-binominal regression model was used to compare the prevalence of H. pylori infection between seven geographic areas.

RESULTS

The overall prevalence of H. pylori infection was 37.6% in women and 43.2% in men. Among seven geographic areas, Hokkaido showed the lowest prevalence (29.4%), while Yamagata Prefecture represented the highest (54.5%). The prevalence of H. pylori infection was highest in the 1940-1949 birth cohort and then decreased in the ensuing birth cohorts; the risk ratio (RR) was 0.85 (95% confidence interval (CI) 0.84-0.87) for changes in the 10-year birth cohort. Individuals in Yamagata Prefecture had the highest RR of acquiring H. pylori infection in all three birth cohorts (RR = 1.53 for 1940, RR = 1.69 for 1950, and RR = 1.85 for 1960) when compared with those in Hokkaido.

CONCLUSIONS

The prevalence of H. pylori infection increases with age and exhibits geographic variation in Japan. There has been a striking decrease in the prevalence of H. pylori infection, especially in younger Japanese populations.

Effects of polymorphisms of innate immunity genes and environmental factors on the risk of noncardia gastric cancer

Purpose

Increasing evidence suggests that polymorphisms in innate immunity genes are associated with Helicobacter pylori-induced inflammation and may influence susceptibility in developing noncardia gastric cancer. Therefore, we investigate the effect of polymorphisms of innate immunity genes and interactions with environmental factors in the Korean population.

Materials and Methods

We genotyped four polymorphisms of TLR2 (rs1898830), TLR4 (rs10983755 and rs10759932), and CD14 (rs2569190) in a case-control study of 487 noncardia gastric cancer patients and 487 sex- and age-matched healthy controls. Polytomous logistic regression models were used to detect the effects of genetic polymorphisms and environmental factors, which were stratified by the histological type of gastric cancer.

Results

TLR4 rs10983755 A carriers were found to have higher risk of intestinal-type noncarida gastric cancer than G homozygotes (odds ratio [OR], 1.41; 95% confidence interval [CI], 1.01 to 1.97), but other genetic variants showed no association with the risk of noncardia gastric cancer. Among H. pylori-positive participants, smokers carrying TLR4 rs10983755 A had a higher risk of intestinal-type gastric cancer than nonsmoking TLR4 rs10983755 G homozygotes (OR, 4.28; 95% CI, 2.12 to 8.64). In addition, compared with tap water, other drinking water sources during childhood were found to be associated with the elevated risk of intestinal-type gastric cancer, and these associations were slightly stronger among TLR4 rs10983755 A carriers.

Conclusion

The genetic polymorphisms of innate immunity genes are associated with the development of intestinal-type noncardia gastric cancer and these associations may differ in accordance to an exposure to certain environmental factors.

Effects of polymorphisms of innate immunity genes and environmental factors on the risk of noncardia gastric cancer

PURPOSE

Increasing evidence suggests that polymorphisms in innate immunity genes are associated with Helicobacter pylori-induced inflammation and may influence susceptibility in developing noncardia gastric cancer. Therefore, we investigate the effect of polymorphisms of innate immunity genes and interactions with environmental factors in the Korean population.

MATERIALS AND METHODS

We genotyped four polymorphisms of TLR2 (rs1898830), TLR4 (rs10983755 and rs10759932), and CD14 (rs2569190) in a case-control study of 487 noncardia gastric cancer patients and 487 sex- and age-matched healthy controls. Polytomous logistic regression models were used to detect the effects of genetic polymorphisms and environmental factors, which were stratified by the histological type of gastric cancer.

RESULTS

TLR4 rs10983755 A carriers were found to have higher risk of intestinal-type noncarida gastric cancer than G homozygotes (odds ratio [OR], 1.41; 95% confidence interval [CI], 1.01 to 1.97), but other genetic variants showed no association with the risk of noncardia gastric cancer. Among H. pylori-positive participants, smokers carrying TLR4 rs10983755 A had a higher risk of intestinal-type gastric cancer than nonsmoking TLR4 rs10983755 G homozygotes (OR, 4.28; 95% CI, 2.12 to 8.64). In addition, compared with tap water, other drinking water sources during childhood were found to be associated with the elevated risk of intestinal-type gastric cancer, and these associations were slightly stronger among TLR4 rs10983755 A carriers.

CONCLUSION

The genetic polymorphisms of innate immunity genes are associated with the development of intestinal-type noncardia gastric cancer and these associations may differ in accordance to an exposure to certain environmental factors.

Introduction of an examination and treatment for Helicobacter pylori infection in high school health screening

BACKGROUND

Recently, a significant relationship between gastric cancer and Helicobacter pylori infection has been proven. The purpose of this study was to elucidate the actual conditions of H. pylori infection in Japanese teenagers.

METHODS

The study subjects were students at a certain high school between 2007 and 2009. They were first examined with a urinary rapid test kit based on immunochromatographic technology [corrected] for detection of the antibody to H. pylori (RAPIRAN®). [corrected]. Students who tested positive on this screening examination visited Shinshu University Hospital and received esophagogastroduodenoscopy, and biopsy samples were taken to examine their H. pylori status. The resolution of H. pylori infection was assessed by urea breath test.

RESULTS

For 3 years, 1,224 of 1,232 students (99.4%) received a screening examination for H. pylori infection. Sixty-four of these 1,224 students (5.2%) were found to be positive for H. pylori. Thirty of these 64 H. pylori-positive students visited our hospital, and 24 of them (80%) were confirmed to be infected by H. pylori. The most common endoscopic findings for students with H. pylori infection were nodular gastritis (58.3%) and closed-type atrophic gastritis (45.8%). Histological findings showed no evidence of intestinal metaplasia, except in one of the students. All 24 students were successfully cured of H. pylori infection. If this procedure were to be introduced into the nationwide health screening at Japanese high schools, we calculated that the cost of the prevention of a gastric cancer would be 454,073 yen for each person.

CONCLUSIONS

The low rate of prevalence of H. pylori infection in Japanese teenagers would make it possible to perform examinations and carry out treatment for this infection in high school health screenings from the standpoint of medical economy.

Transmission pathway of Helicobacter pylori: does food play a role in rural and urban areas?

Helicobacter pylori is a Gram-negative microaerophilic bacterium that has colonized the human gastric mucosa. This infection is very common and affects more than half of the human population. The prevalence is however unbalanced between rural developing areas (more than 80%) and urban developed areas (less than 40%). H. pylori is responsible for several pathologies, such as gastritis, peptic ulcer and gastric cancer but its transmission pathway is still not clear. The risk factors for H. pylori infection include poor social and economic development; poor hygienic practices; absence of hygienic drinking water; and unsanitary prepared food. There is evidence supporting a gastro-oral, oral-oral and faecal-oral transmission, but no predominant mechanism of transmission has been yet identified. Transmission may occur in a vertical mode (e.g. from parents to child) or in a horizontal mode (across individuals or from environmental contamination). In either case, the involvement of water and food cannot be excluded as vehicles or sources of infection. Indirect evidence of presence of H. pylori in water and food, namely the detection of its DNA and survival studies after artificial contamination of food and water has been described. This paper reviews data both favourable and against the role of water and food in the transmission of H. pylori, exploring their role as a potential transmission vehicle for person-to-person and food-chain transmission. The likelihood of the transmission pathway in developing rural and developed urban areas appears to be different. In developed areas, person-to-person transmission within families appears to be dominant, while in the rural developing areas the transmission pathway appears to be more complex. In this later case, the transmission by contaminated food, water, or via intensive contact between infants and non-parental caretakers may have a greater influence than within-family transmission.

Host, family and community proxies for infections potentially associated with leukaemia

Three hypotheses have proposed the involvement of infections in the aetiology of childhood leukaemia, suggesting either a specific leukaemogenic infection or a series of common infections that lead to a dysregulation of the immune system. Much of the evidence for the link with infections has been based on epidemiological observations, often using proxy measures of infection. Proxy measures include population mixing, parental occupation, age distribution of incidence, spatial and space-time clustering of cases, birth order and day care during infancy. This paper discusses the proxies used and examines to what extent a commonly used proxy measure, birth order, is a fair representation of either specific infections or general infectious load. It is clear that although leukaemia, and other diseases, may be linked with infections, one needs to (1) measure specific and general infections with more accuracy and (2) understand how proxy measures relate to real infections in the population.

Effect of sibling number in the household and birth order on prevalence of Helicobacter pylori: a cross-sectional study

BACKGROUND

Infection with Helicobacter pylori (H. pylori) is acquired mainly in childhood, with studies demonstrating this is related to living conditions. Effects of sibling number and birth order on prevalence of infection have not been extensively studied.

METHODS

The authors performed a cross-sectional survey of adults, aged between 50 and 59 years, previously involved in a community-screening programme for H. pylori in Leeds and Bradford, UK. Prevalence of H. pylori was assessed at baseline with urea breath test. All individuals who were alive, and could be traced, were contacted by postal questionnaire in 2003 obtaining information on number of siblings and birth order. Data concerning childhood socioeconomic conditions were stored on file from the original study.

RESULTS

3928 (47%) of 8407 original participants provided data. Prevalence of infection increased according to sibling number (20% in those with none vs 63% with eight or more). Controlling for childhood socioeconomic conditions and birth order using multivariate logistic regression, infection odds were substantially increased with three siblings compared with none [odds ratio (OR) 1.51; 95% confidence interval (CI) 1.06-2.15], and a gradient of effect continued up to eight or more siblings (OR 5.70; 95% CI 2.92-11.14). Odds of infection also increased substantially with birth order, but the positive gradient disappeared on adjustment for sibling number and childhood socioeconomic conditions.

CONCLUSIONS

: In this cross section of UK adults, aged 50-59 years, sibling number in the household, but not birth order, was independently associated with prevalence of H. pylori infection.

Intrafamilial transmission of Helicobacter pylori among the population of endemic areas in Japan

BACKGROUND

Helicobacter pylori (H. pylori) infection is a worldwide phenomenon related to several gastrointestinal diseases. However, because many aspects concerning the route of transmission remain unclear, we performed this epidemiologic study to clarify the route of intrafamilial transmission of H. pylori.

MATERIALS AND METHODS

A retrospective study was performed in three widely separate areas in Japan to investigate the prevalence of H. pylori infection. In 1993, 613 residents were tested as were 4136 in 2002, including 1447 family members of 625 families. Antibody to H. pylori (anti-H. pylori) was determined by enzyme-linked immunosorbent assay.

RESULTS

In 2002, the age-adjusted anti-H. pylori prevalence in Hoshino Village (67.5%) was significantly higher than in Kasuya Town (55.0%) and in Ishigaki City (54.7%) (p < .0001, p = .0039, respectively). The age-adjusted anti-H. pylori prevalence of Ishigaki City significantly decreased from 1993 (68.4%) to 2002 (52.5%), showing an age cohort effect. However, the prevalence did not significantly differ in children aged 0-6 years of Ishigaki City between 1993 (9.6%) and 2002 (10.3%). A familial analysis in 2002 demonstrated that the prevalence of anti-H. pylori was significantly higher in children with anti-H. pylori-positive (21.6%, 22 of 102) than with -negative mothers (3.2%, 3 of 95) (p < .0001, by Mantel-Haenszel test), whereas there was no significant difference between children with anti-H. pylori-positive and -negative fathers. Moreover, the prevalence was significantly higher in wives with anti-H. pylori-positive (64.0%, 208 of 325) than with -negative husbands (46.5%, 80 of 172) (p = .0071, by Mantel-Haenszel test) and in husbands with anti-H. pylori-positive (72.2%, 208 of 288) than with -negative wives (56.0%, 117 of 209) (p = .0106, by Mantel-Haenszel test).

CONCLUSIONS

In the last decade, H. pylori infection decreased in the general population of Japan by improvement of general hygiene conditions, but did not differ in young children, most likely because of mother-to-child transmission.

Socioeconomic position and the risk of gastric and oesophageal cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST)

OBJECTIVES

To evaluate the association of socioeconomic position with adenocarcinoma of the oesophagus and stomach.

METHODS

The European Prospective Investigation into Cancer and Nutrition (EPIC) cohort comprises about 520 000 participants mostly aged 35-70 years. Information on diet and lifestyle was collected at recruitment. After an average follow-up of 6.5 years, 268 cases with adenocarcinoma of the stomach and 56 of the oesophagus were confirmed. We examined the effect of socioeconomic position on cancer risk by means of educational data and a computed Relative Index of Inequality (RII). In a nested case-control study, adjustment for Helicobacter pylori (H. pylori) infection was performed.

RESULTS

Higher education was significantly associated with a reduced risk of gastric cancer [vs lowest level of education, hazard ratio (HR): 0.64, 95% Confidence intervals (CI): 0.43-0.98]. This effect was more pronounced for cancer of the cardia (HR: 0.42, 95% CI: 0.20-0.89) as compared to non-cardia gastric cancer (HR: 0.66, 95% CI: 0.36-1.22). Additionally, the inverse association of educational level and gastric cancer was stronger for cases with intestinal (extreme categories, HR: 0.13, 95% CI: 0.04-0.44) rather than diffuse histological subtype (extreme categories, HR: 0.71 95% CI: 0.37-1.40). In the nested case-control study, inverse but statistically non-significant associations were found after additional adjustment for H. pylori infection [highest vs lowest level of education: Odds ratio (OR) 0.53, 95% CI: 0.24-1.18]. Educational level was non-significantly, inversely associated with carcinoma of the oesophagus.

CONCLUSION

A higher socioeconomic position was associated with a reduced risk of gastric adenocarcinoma, which was strongest for cardia cancer or intestinal histological subtype, suggesting different risk profiles according to educational level. These effects appear to be explained only partially by established risk factors.

A seroepidemiology survey on Helicobacter pylori infection in rural families

AIM: To estimate the prevalence of H. pylori infection in rural families, and to investigate the transmission route of H. pyloriinfection.

METHODS: A cross-sectional study was carried out among 263 villagers from 71 families in September 2004 in Zunhua city, Hebei province. Each subject was interviewed using a unified questionnaire. Blood sample of 5 mL was collected for the antibody examination by enzyme-linked immunosorbent assay (ELISA). Western blot analysis was performed to distinguish the infected strains, and compared with two standard strains NCTC 11637 and CAPM N111, respectively. Similarity analysis was then carried out with Quantity one 4.1.1 software, which is special for photographs of electrophoresis.

RESULTS: The seroprevalence of H. pylori infection in residents of this area was of medium level in our country, and it was not associated with gender. In this area, the risk factors of infection were bad living conditions, overcrowding and possession of pigs during childhood, as well as several generations eating together, less vinegar and fruit intake. The overall prevalence and serum level of anti-H. pylori antibodies in 263 subjects was 57.41% and 0.911 ± 0.810 mg/L, respectively. In males, they were 60.50% and 0.948 ± 0.843 mg/L, while 54.86% and 0.880 ± 0.748 mg/L in females, respectively (P > 0.05). Infection clustered within families, and 60% and 51.35% of the children with two or at least one infected parent were H. pylori-positive, while the prevalence rate in the children with both parents uninfected was only 11.11% (P < 0.05). Western blot showed that the antibodies of the residents living in the area were similar in bands (F = 1.22, P > 0.05).

CONCLUSION: The prevalence of H. pylori in residents of this area was of medium level in our country. Infection clusters within families, and the status of parents' infection can affect that of the children.

Immune responses to Helicobacter pylori colonization: mechanisms and clinical outcomes

Helicobacter pylori colonizes the stomachs of half of the world's population and usually persists in the gastric mucosa of human hosts for decades or life. Although most H. pylori-positive people are asymptomatic, the presence of H. pylori is associated with increased risk for the development of peptic ulcer disease, gastric adenocarcinoma and gastric lymphoma. The development of a sustained gastric inflammatory and immune response to infection appears to be pivotal for the development of disease. During its long co-existence with humans, H. pylori has evolved complex strategies to maintain a mild inflammation of the gastric epithelium while limiting the extent of immune effector activity. In this review, the nature of the host immune response to H. pylori infection and the mechanism employed by the bacterium to evade them is considered. Understanding the mechanisms of colonization, persistence and virulence factors of the bacterium as well as the innate and adaptive immune responses of the host are critically important for the development of new strategies to prevent the development of H. pylori-induced gastroduodenal disease.

Long-term outcomes after Helicobacter pylori eradication with second-line, bismuth-containing quadruple therapy in Korea

OBJECTIVES

To determine the long-term outcomes in terms of Helicobacter pylori and ulcer recurrence after second-line eradication with bismuth-containing quadruple regimens in Korea.

METHODS

Sixty-seven patients with peptic ulcer disease after successful eradication using second-line quadruple therapies were prospectively followed up 1 month after treatment and then every 6 months or when dyspeptic symptoms reappeared to ascertain H. pylori and ulcer status.

RESULTS

Three patients were lost during follow-up. The median duration of follow-up of the remaining 64 patients was 26.8 months. H. pylori recurrence occurred in 11 of these 64 patients (17.2%), giving a calculated reinfection rate of 6.0% per patient-year. Only one of the 11 patients was reinfected by 12 months after treatment completion. Four of 11 patients (36.4%) who became reinfected experienced peptic ulcer recurrence, but none of 53 patients who were not reinfected experienced recurrence. No evidence was obtained to indicate that the reinfection rate depended on the age, sex, ulcer location, or eradication regimens. The relapse of dyspeptic symptoms was the only factor predictive of H. pylori recurrence.

CONCLUSION

This study suggests that the recurrence rate of H. pylori at 1 year after second-line, bismuth-containing quadruple therapy is low, but the annual reinfection rate is as high as 6%. Surveillance for H. pylori reinfection facilitating peptic ulcer recurrence may be warranted even after a second eradication, especially when dyspeptic symptoms reappear in Korea.

A conceptual model of water's role as a reservoir in Helicobacter pylori transmission: a review of the evidence

Helicobacter pylori infection plays a role in the development of chronic gastritis, peptic ulcer and gastric cancer, yet the route of transmission into susceptible hosts remains unknown. Studies employing microbiological techniques have demonstrated that H. pylori has the ability to survive when introduced into water and that H. pylori is present in water and other environmental samples all over the world. Epidemiological studies have shown that water source and exposures related to water supply, including factors related to sewage disposal and exposure to animals, are risk factors for infection. This review describes the microbiological and epidemiological evidence for, and proposes a model of, waterborne H. pylori transmission outlining important features in the transmission cycle. In the model, humans and animals shed the bacteria in their faeces and the mechanisms for entry into water, and for survival, ingestion and infection are dependent upon a range of environmental influences. Verification of the proposed model pathways has important implications for public-health prevention strategies.

Serum pepsinogen values and Helicobacter pylori status among control subjects of a nested case-control study in the JACC study

BACKGROUD: Helicobacter pylori infection and serum pepsinogen values are strongly related with stomach cancer. The aim of this study was to know what were these factors among general population.

METHODS: Subjects were randomly selected 633 control subjects in a nested case-control study for risk of stomach cancer. Most of them were from rural areas of Japan. Using frozen sera, pepsinogen I (PG I) and II (PG II) values and H. pylori antibody were measured. Those with PG I less than 50 ng/mL and the ratio of PG I to PG II (PG I/II) was less than 2.0 were defined as severe, those with PG I less than 70 ng/ml and PG I/II less than 3.0 were defined as mild and the other subjects were defined as no serological atrophy.

RESULTS: About 70% of the subjects were H. pylori seropositive and the seroprevalence did no depend on age or sex. Percentages of those with severe serological atrophy increased with age from 10% in those aged 40-49 years to 38% in 70 and more, and percentages of those with mild serological atrophy were about 30% independent of age.

CONCLUSIONS: The subjects, who were expected to represent populations of rural area of Japan, had high prevalence of both H. pylori infection and serological atrophy of gastric mucosa. These facts should be considered in discussing results of the nested case-control study.

Seroconversion and seroreversion of Helicobacter pylori antibodies over a 9-year period and related factors in Japanese adults

BACKGROUND

There are still insufficient data on the frequency of seroconversion and seroreversion of Helicobacter pylori antibodies. The frequency of serochange and related factors were investigated in this study over 9 years.

SUBJECTS AND METHODS

Using sera from 3104 workers who underwent health checks in 1989 and again in 1998, H. pylori antibodies were measured. Those with intermediate serology were excluded from the study. Information on past history was collected using a questionnaire.

RESULTS

Of the 912 seronegative and 1286 seropositive subjects in 1989, seroconversion was observed in 57 and seroreversion in 91 subjects. Seroconversion and seroreversion rates over the 9-year period were 6.3% and 7.1%, respectively, giving rates per 1000 person-years (with 95% confidence interval) of 7.0 (5.2-8.7) and 7.9 (6.3-9.4), respectively. Subjects that reported abdominal symptoms or gastric fiberscope use showed significantly higher seroconversion rates than controls (8.7 vs. 4.5 and 9.2 vs. 1.6, respectively), which remained significant after adjustment for age and gender. Those with a history of duodenal ulcers, a smoking habit or a drinking habit showed significantly lower seroreversion rates than controls (3.5 vs. 8.9, 5.4 vs. 9.2 and 5.9 vs. 13.3, respectively). After adjustment, the association between seroreversion and smoking habit disappeared, while the associations with history of duodenal ulcers and drinking habit remained.

CONCLUSIONS

Those with a history of nonspecific abdominal symptoms and those with a history of gastric fiberscope use showed higher seroconversion rates. Alcohol consumption and duodenal ulcers may inhibit the autoeradication of H. pylori, possibly through increased acid secretion.