The seroepidemiology of Helicobacter pylori infection in Australia

Geospatial analysis of Helicobacter pylori infection in South Australia: Should location influence eradication therapy?

BACKGROUND AND AIM

Rates of antimicrobial-resistant Helicobacter pylori infection are rising globally; however, geospatial location and its interaction with risk factors for infection have not been closely examined.

METHODS

Gastric biopsy specimens were collected to detect H. pylori infection at multiple centers in Adelaide, South Australia, between 1998 and 2017. The geospatial distribution of antibiotic-resistant H. pylori in the Greater Adelaide region was plotted using choropleth maps. Moran's I was used to assess geospatial correlation, and multivariate linear regression (MLR) was used to examine associations between migration status, socioeconomic status, age, gender, and rates of H. pylori positivity and antibiotic resistance. Geographically weighted regression (GWR) was used to determine the extent to which the associations varied according to geospatial location.

RESULTS

Of 20 108 biopsies across 136 postcodes within the Greater Adelaide region, 1901 (9.45%) were H. pylori positive. Of these, 797 (41.9%) displayed clarithromycin, tetracycline, metronidazole, or amoxicillin resistance. In MLR, migration status was associated with the rate of H. pylori positivity (β = 3.85% per 10% increase in a postcode's migrant population; P < 0.001). H. pylori positivity and resistance to any antibiotic were geospatially clustered (Moran's I = 0.571 and 0.280, respectively; P < 0.001 for both). In GWR, there was significant geospatial variation in the strength of the migrant association for both H. pylori positivity and antibiotic resistance.

CONCLUSION

Our study demonstrates the heterogeneous geospatial distribution of H. pylori positivity and antibiotic resistance, as well as its interaction with migrant status. Geographic location and migrant status are important factors to consider for H. pylori eradication therapy.

Mechanisms for the sex-specific effect of H. pylori on risk of gastroesophageal reflux disease and Barrett's oesophagus

BACKGROUND

Mechanisms for how Helicobacter pylori infection affects risk of gastroesophageal reflux disease (GERD) and Barrett's oesophagus (BE) are incompletely understood and might differ by sex.

METHODS

In a case-control study nested in the Melbourne Collaborative Cohort Study with 425 GERD cases and 169 BE cases (identified at 2007-10 follow-up), we estimated sex-specific odds ratios for participants who were H. pylori seronegative versus seropositive at baseline (1990-94). To explore possible mechanisms, we 1) compared patterns of H. pylori-induced gastritis by sex using serum pepsinogen-I and gastrin-17 data and 2) quantified the effect of H. pylori seronegativity on BE mediated by GERD using causal mediation analysis.

RESULTS

For men, H. pylori seronegativity was associated with 1.69-fold (CI:1.03-2.75) and 2.28-fold (CI:1.27-4.12) higher odds of GERD and BE, respectively. No association was observed for women. H. pylori-induced atrophic antral gastritis was more common in men (68%) than in women (56%; p=0.015). For men, 5 of the 15 per 1,000 excess BE risk from being seronegative was mediated by GERD.

CONCLUSIONS

Men, but not women, who were H. pylori seronegative had increased risks of GERD and BE. A possible explanation might be sex-differences in patterns of H. pylori-induced atrophic antral gastritis, which could lead to less erosive reflux for men. Evidence of GERD mediating the effect of H. pylori on BE risk among men supports this proposed mechanism.

IMPACT

The findings highlight the importance of investigating sex differences in the effect of H. pylori on risk of GERD and BE in future studies.

Epidemiology of Helicobacter pylori in Australia: a scoping review

Background

Helicobacter pylori (H. pylori), a bacterium implicated in the development of peptic ulcer and gastric cancer, is estimated to infect around half the world's population. Its prevalence in Australia is unclear. This scoping review aimed to evaluate all Australian literature providing estimates of the prevalence of H. pylori.

Methods

Australian studies examining H. pylori prevalence from 1982 onwards were eligible for inclusion. Medline, Embase and Scopus databases, and grey literature sources, were searched. Two independent reviewers undertook a two-stage screening process. Data were extracted by two independent reviewers using a pre-specified template.

Results

Of 444 identified studies, 75 were included in the review. H. pylori prevalence in Australian population-based studies (n = 8) ranged from 38.0% in 1991 to 15.1% in 2002; however, estimated prevalence across all non-clinical population studies in diverse sub-groups (n = 29) has varied dramatically. Decreased prevalence has been more marked in populations with gastrointestinal symptoms and conditions compared to non-clinical populations. Data on H. pyloriprevalence in vulnerable populations are lacking.

Conclusions

This is the first scoping review of Australian studies reporting H. pylori prevalence. A wide range of study designs, population groups, geographic regions, and diagnostic methods was included, involving data collected over a 50-year period (1969 to 2018). The summary of H. pylori prevalence estimates over time in this review points to a decrease in prevalence in Australia, particularly among populations with gastrointestinal symptoms and illnesses; however, it is unknown whether there is inequity in prevalence trends across vulnerable sub-groups of the Australian population. Future research and interventions supporting the health and wellbeing of vulnerable populations is required to ensure equitable health gains are made for all.

Gastrointestinal Adenocarcinoma Incidence and Survival Trends in South Australia, 1990-2017

Simple Summary

This study from South Australia using the state’s Cancer Registry data provides compelling evidence for a significant increase in the incidence of young-onset (18–50 years) gastrointestinal (oesophageal, stomach, colon and rectum, and pancreas) adenocarcinomas over the last three decades. The trend observed in the young cohort was not mirrored in older individuals >50 years. This increased incidence, though noted in both sexes, was more pronounced in males compared to females. Survival in the young-onset adenocarcinoma cohort was only seen in patients with colorectal cancers, but not oesophagus, stomach and pancreas. This study calls for a concerted effort aimed at determining the sociodemographic factors underlying this disturbing trend with the aim of developing preventative strategies.

Abstract

Background & Aims: Globally, there has been a concerning rise in the incidence of young-onset cancers. The aim of this study was to provide trends in the incidence and survival of gastrointestinal adenocarcinomas (oesophagus, stomach, pancreas, and colorectal) in South Australia over a 27-year period. Methods: This is a cross-sectional analysis of a prospective longitudinal database including all cases of gastrointestinal adenocarcinomas prospectively reported to the South Australian (State) Cancer Registry from 1990 to 2017. Results: A total of 28,566 patients diagnosed with oesophageal, stomach, pancreatic, or colorectal adenocarcinoma between 1990 and 2017 were included in the study. While the overall incidence for gastrointestinal adenocarcinomas in individuals >50 years has decreased since 2000 (IRR of 0.97 (95% CI 0.94–1.00; p = 0.06)) compared to 1990–1999, the rate amongst individuals aged 18–50 has significantly increased (IRR 1.41 (95% CI 1.27–1.57; p < 0.001)) during the same reference time period. Although noted in both sexes, the rate of increase in incidence was significantly greater in males (11.5 to 19.7/100,000; p < 0.001). The overall survival from adenocarcinomas across all subsites improved in the >50-year cohort in the last decade (HR 0.89 (95% CI 0.86–0.93; p < 0.001)) compared to 1990–1999. In individuals aged 18–50 years, there has only been a significant improvement in survival for colorectal cancer (HR 0.82 (95% CI 0.68–0.99; p < 0.04)), but not the other subsites. A lower overall survival was noted for males in both age cohorts (18–50 years—HR 1.24 (95% CI 1.09–1.13; p < 0.01) and >50 years—HR 1.13 (95% CI 1.10–1.16; p < 0.001), respectively) compared to females. Conclusions: This study from South Australia demonstrates a significant increase in young-onset gastrointestinal adenocarcinomas over the last 28 years, with a greater increase in the male sex. The only significant improvement in survival in this cohort has been noted in colorectal cancer patients.

Increasing Helicobacter pylori clarithromycin resistance in Australia over 20 years

OBJECTIVES

Helicobacter pylori infection is responsible for considerable morbidity and mortality worldwide, and eradication rates are falling in many countries, primarily due to clarithromycin and metronidazole resistance. However, there is a paucity of contemporary Australian data, which we sought to address by evaluating local rates of resistance of H. pylori to amoxicillin, clarithromycin, metronidazole, and tetracycline over the past 20 years.

DESIGN

All gastric biopsy specimens collected at endoscopy to detect H. pylori infection at a single centre underwent routine culture and antibiotic susceptibility testing between 1998-2017. Specimens from 12,842 patients were cultured for H. pylori, of which 1,473 positive cultures were tested for antibiotic susceptibility.

RESULTS

Antibiotic resistance to clarithromycin increased by 3.7% per year (IRR 1.037, p=0.014) over 20 years, with a corresponding 5.0% annual increase in minimum inhibitory concentration (MIC) (OR 1.050, p<0.001). Since 2010, average clarithromycin resistance has exceeded 20%, with >25% of isolates resistant in the last 2 years of data capture. By contrast, rates of resistance to metronidazole (35.3%), amoxicillin (0.14%) and tetracycline (0.34%) and their MICs have remained stable. Review of a representative sample of these patients (n=120, 8%) revealed that only 5% had documented prior H. pylori eradication therapy.

CONCLUSIONS

Over the last 20 years there has been a substantial rise in clarithromycin resistance, with stable metronidazole resistance and low rates of resistance to amoxicillin and tetracycline. Current first line H. pylori eradication therapy may fail to achieve adequate eradication rates, and optimal first line therapy in Australia should be revisited. This article is protected by copyright. All rights reserved.

The future excess fraction of cancer due to lifestyle factors in Australia

BACKGROUND

Many cancers are caused by exposure to lifestyle, environmental, and occupational factors. Earlier studies have estimated the number of cancers occurring in a single year which are attributable to past exposures to these factors. However, there is now increasing appreciation that estimates of the future burden of cancer may be more useful for policy and prevention. We aimed to calculate the future number of cancers expected to arise as a result of exposure to 23 modifiable risk factors.

METHODS

We used the future excess fraction (FEF) method to estimate the lifetime burden of cancer (2016-2098) among Australian adults who were exposed to modifiable lifestyle, environmental, and occupational risk factors in 2016. Calculations were conducted for 26 cancer sites and 78 cancer-risk factor pairings.

RESULTS

The cohort of 18.8 million adult Australians in 2016 will develop an estimated 7.6 million cancers during their lifetime, of which 1.8 million (24%) will be attributable to exposure to modifiable risk factors. Cancer sites with the highest number of future attributable cancers were colon and rectum (n = 717,700), lung (n = 380,400), and liver (n = 103,200). The highest number of future cancers will be attributable to exposure to tobacco smoke (n = 583,500), followed by overweight/obesity (n = 333,100) and alcohol consumption (n = 249,700).

CONCLUSION

A significant proportion of future cancers will result from recent levels of exposure to modifiable risk factors. Our results provide direct, pertinent information to help determine where preventive measures could best be targeted.

Combinations of antibiotics and vonoprazan for the treatment of Helicobacter pylori infections-Exploratory study

BACKGROUND

Vonoprazan fumarate is a novel potassium-competitive acid blocker more effective in suppressing acid production than proton pump inhibitors (PPIs) and when combined with antibiotics has been used to eradicate Helicobacter pylori (H. pylori) infection. However, it has not yet been examined in an Australian setting. This study aimed to report on the efficacy and safety of vonoprazan-containing antibiotic combination therapies in the eradication of H. pylori.

METHODS

A single-center, exploratory, clinical review of patients 18 years or over, positive for H. pylori on Urea Breath Test (UBT), and/or histopathology who underwent a 10-day treatment of combination antibiotics plus vonoprazan between January 2017 and September 2019 was conducted. Eleven different combinations of antibiotics that included 2-5 different antibiotics predominantly amoxicillin, rifabutin, levofloxacin, furazolidone, nitazoxanide, and tetracycline were included. The eradication success was based on negative UBT results and/or histopathology results after the treatment. Descriptive statistics were summarized.

RESULTS

One hundred and fifty-three patients (Female n = 74, 48%) with a positive for H. pylori were treated with vonoprazan-containing antibiotic combination therapy during the study period. Of the 153 patients, 48 (31%) had previously failed a PPI-based H. pylori treatment. Follow-up was available for 66/153 (43%) patients. In those who completed follow-up, overall eradication was achieved in 97% (64/66) of patients. In the subgroup of patients treated for the first time, eradication was achieved in 100% (44/44). In those who had failed prior, non-vonoprazan-containing treatment, eradication was achieved in 91% (20/22) of patients.

CONCLUSIONS

Vonoprazan-containing antibiotic therapy is an effective H. pylori eradication treatment. It is capable of achieving 100% efficacy in patients treated for the first time and even 91% efficacy in patients with previous eradication failure. Subsequent studies utilizing a factorial design will be needed to optimize each regimen as most regimens contained more than two antibiotics.

Prospective Phase II trial of radiation therapy in localised non-gastric marginal zone lymphoma with prospective evaluation of autoimmunity and Helicobacter pylori status: TROG 05.02/ALLG NHL15

BACKGROUND

This Phase 2 multicentre trial in localised non-gastric marginal zone lymphoma (MZL) evaluated the effectiveness and safety of radiotherapy and documented markers of autoimmunity and Helicobacter pylori infection.

PATIENTS AND METHODS

Eligible patients had Stages I and II or paired-organ, non-gastric MZL. Bone marrow evaluation, autoantibody panel, and H. pylori evaluation were mandatory. Involved-field or involved-site radiotherapy was delivered to 24-30.6 Gy. Detected H. pylori infections underwent eradication.

RESULTS

Between 2006 and 2014, six centres enrolled 70 patients, and 68 commenced treatment. The median age was 59 (range: 23-84) years, and 31 (46%) were male. Overall, 55 patients had Stage I disease, nine patients had Stage II disease, and four patients had paired organ-confined disease. Involved extranodal sites with three or more cases were orbital (n = 18), conjunctiva (n = 13), lacrimal (n = 8), skin (n = 8), salivary (n = 7), and muscle (n = 4). Eight patients had primary nodal MZL. At the median follow-up of 5 years (range 0.7-9.4), progression-free survival and overall survival were 79% and 95%, respectively. One lymphoma-related death and two in-field failures (after 25 and 30 Gy, respectively) occurred. Distant relapse sites were skin (n = 2), lymph nodes (n = 2), duodenum, stomach, muscle, and conjunctiva (1 each). No paired-organ MZL relapsed. Apart from cataracts (n = 18), only three treatment-related late grade ≥3 adverse events occurred. Autoantibodies or autoimmune events were detected in 26 of 68 patients (38%). H. pylori infection was detected in 15 of 63 patients (24%) tested. Neither autoimmunity nor H. pylori was detected in 27 of 68 patients (40%).

CONCLUSIONS

Radiotherapy was a potentially curative treatment with low toxicity in localised non-gastric MZL. Autoimmunity, H. pylori infection or both were detected in 60% of patients.

Antibiotic resistance of Helicobacter pylori in Australia and New Zealand: A systematic review and meta-analysis

OBJECTIVE

While the global prevalence of antibiotic-resistant Helicobacter pylori (H. pylori) is increasing, there is much regional variation, and local data are required to guide eradication therapy. We performed a systematic review and meta-analysis to determine rates of H. pylori antibiotic resistance in Australia and New Zealand.

STUDY DESIGN

Random effects meta-analysis of data from 15 published studies and three published abstracts reporting prevalence of primary or secondary H. pylori antibiotic resistance in Australasia.

DATA SOURCES

PubMed, EMBASE, MEDLINE, PROSPERO, and the Cochrane Library were searched until August, 2020.

DATA SYNTHESIS

Fifteen published studies and three published abstracts were identified; one study was excluded due to high risk of bias. Seventeen studies conducted between 1996 and 2013 were included in the final analysis, 12 reporting primary and five reporting secondary antibiotic resistance. Prevalence of primary resistance was clarithromycin 7.4% (95% confidence interval [CI], 5.3-9.7%), metronidazole 50.0% (95%CI, 23.9-56.1%), fluoroquinolones 3.7% (95%CI, 0.004-14.8%), and both amoxicillin and tetracycline <0.5%. Subgroup analysis (last 20 years) showed doubling of clarithromycin resistance to 16.1% (95%CI 11.2-21.7%) with other resistance stable. Prevalence of secondary resistance was high for all antibiotics, particularly clarithromycin 78.7% (95%CI, 64.1-90.1%) and metronidazole 68.3% (95%CI, 59.9-76.1%).

CONCLUSIONS

The outcomes reveal an increase in primary H. pylori clarithromycin resistance since the year 2000, while metronidazole resistance has remained stable and primary resistance to amoxicillin, tetracycline, and fluoroquinolones is low. Rates of secondary resistance to metronidazole and clarithromycin are high. The results highlight the need for contemporary local data on antibiotic resistance in Australia and New Zealand.

Appendiceal neoplasm incidence and mortality rates are on the rise in Australia

OBJECTIVES

The study aimed to examine the incidence and mortality rates of appendiceal neoplasms (ANs) in Australia.

METHODS

A retrospective analysis was performed on national data obtained from the Australian Institute of Health and Welfare (AIHW) from 1982 to 2013. Changes to the incidence, and the cancer-specific mortality following the diagnosis of ANs were analyzed over this time period, with stratification performed for histological subtype, gender, and age groups (<50y and ≥50y).

RESULTS

Incidence and mortality rates of ANs increased significantly across both genders and age groups. Incidence rates increased by 415%, from 0.40/100 000 population in 1982 to 2.06/100 000 in 2013. Overall mortality rates increased by 130%, from 0.057/100 000 during 1982-1985 to 0.131/100 000 during 2010-2013. Controlling for age group and gender, the incidence rates increased by 20% every four years (Incidence rate ratio (IRR) = 1.20, 95% confidence interval (CI): 1.17, 1.23, global P value<0.0001), and controlling for age, the mortality rates increased by 8% every four years (IRR = 1.08, 95% CI: 1.00, 1.17, global P-value = 0.0401).

CONCLUSION

The increasing use of CT scanning, improvements in pathological assessment of the appendix, and the growing aging population may have contributed in part to the apparent rise in the incidence of ANs.

Comparison of Bayesian and frequentist methods for prevalence estimation under misclassification

BACKGROUND

Various methods exist for statistical inference about a prevalence that consider misclassifications due to an imperfect diagnostic test. However, traditional methods are known to suffer from truncation of the prevalence estimate and the confidence intervals constructed around the point estimate, as well as from under-performance of the confidence intervals' coverage.

METHODS

In this study, we used simulated data sets to validate a Bayesian prevalence estimation method and compare its performance to frequentist methods, i.e. the Rogan-Gladen estimate for prevalence, RGE, in combination with several methods of confidence interval construction. Our performance measures are (i) error distribution of the point estimate against the simulated true prevalence and (ii) coverage and length of the confidence interval, or credible interval in the case of the Bayesian method.

RESULTS

Across all data sets, the Bayesian point estimate and the RGE produced similar error distributions with slight advantages of the former over the latter. In addition, the Bayesian estimate did not suffer from the RGE's truncation problem at zero or unity. With respect to coverage performance of the confidence and credible intervals, all of the traditional frequentist methods exhibited strong under-coverage, whereas the Bayesian credible interval as well as a newly developed frequentist method by Lang and Reiczigel performed as desired, with the Bayesian method having a very slight advantage in terms of interval length.

CONCLUSION

The Bayesian prevalence estimation method should be prefered over traditional frequentist methods. An acceptable alternative is to combine the Rogan-Gladen point estimate with the Lang-Reiczigel confidence interval.

A Longitudinal, Population-Level, Big-Data Study of Helicobacter pylori-Related Disease across Western Australia

Helicobacter pylori, responsible for chronic ulcers and most stomach cancers, infects half of the world’s population. The Urea Breath Test (UBT) is one of the most accurate and reliable non-invasive methods for diagnosing active H. pylori infection. The objective was to use longitudinal, population-wide UBT data for Western Australia to look for H. pylori-related disease patterns. We collected 95,713 UBT results from 77,552 individuals for the years 2010–2015, likely representing all of the UBT samples analysed in Western Australia. Data collected also included sex, age and residential postcode. Other data reported here were inferred via a comparison with the 2011 Australian Census using a specially written Python program. While women appear to have more H. pylori-related disease than men, there is no difference in the disease rates once women’s higher rates of presentation for testing are taken into account. On the other hand, while the treatment strategy for H. pylori infection is generally very effective in Western Australia, failure of the first-line treatment is significantly more common in women than men. Migrants and Aboriginal Australians have elevated rates of H. pylori-related disease, while the rate for non-Aboriginal Australian-born West Australians is very low. However, no significant associations were found with other socio-economic indicators. We conclude that, for some people, H. pylori-related disease is not a solved problem.

Helicobacter pylori associated factors in the development of gastric cancer with special reference to the early-onset subtype

Nowadays, gastric cancer is one of the most common neoplasms and the fourth cause of cancer-related death on the world. Regarding the age at the diagnosis it is divided into early-onset gastric carcinoma (45 years or younger) and conventional gastric cancer (older than 45). Gastric carcinomas are rarely observed in young population and rely mostly on genetic factors, therefore provide the unique model to study genetic and environmental alternations. The latest research on early-onset gastric cancer are trying to explain molecular and genetic basis, because young patients are less exposed to environmental factors predisposing to cancer. In the general population, Helicobacter pylori, has been particularly associated with intestinal subtype of gastric cancers. The significant association of Helicobacter pylori infection in young patients with gastric cancers suggests that the bacterium has an etiologic role in both diffuse and intestinal subtypes of early-onset gastric cancers. In this paper we would like to ascertain the possible role of Helicobacter pylori infection in the development of gastric carcinoma in young patients. The review summarizes recent literature on early-onset gastric cancers with special reference to Helicobacter pylori infection.

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.

Prevalence of Helicobacter pylori infection in newly arrived refugees attending the Migrant Health Service, South Australia

BACKGROUND

To determine the prevalence of Helicobacter pylori infection in the refugee population attending the Migrant Health Service, South Australia, identify demographic factors associated with infection and compare prevalence of infection in refugees with that of the nonrefugee population in Australia.

MATERIALS AND METHODS

Cross-sectional study conducted between October 2010 and August 2013. Monoclonal stool antigen testing for H. pylori infection is performed as part of a comprehensive health assessment for newly arrived refugees. The sample population included 922 adults and children. Outcome measures were (i) prevalence of H. pylori infection (ii) association between demographic factors such as sex, ethnicity and age, and H. pylori infection.

RESULTS

H. pylori infection was detected in 198 (21.5%) participants (95% CI 18.9%-24.3%). The odds of infection were lower in females OR 0.71 (95% CI 0.51-0.98) compared to males. Compared to Middle Eastern participants, the odds of infection were 1.75 (95% CI 1.17-2.62) times higher in African and 1.90 (95% CI 1.10-3.26) times higher in Burmese participants. Infection was not associated with age.

DISCUSSION AND CONCLUSION

H. pylori infection is common among newly arrived refugees. The long latency of infection to development of complications and the availability of testing and relatively effective eradication regimens all add weight to a decision to screen in this population.

Epidemiology, clinical impacts and current clinical management of Helicobacter pylori infection

Helicobacter pylori infection is a major cause of morbidity and mortality worldwide. More than 50% of the global population is estimated to be infected. Differences in prevalence exist within and between countries, with higher prevalence seen among people with lower socio-economic status. Most transmission of infection occurs early in life, predominantly from person to person in the family setting. H. pylori is the cause of most peptic ulcer disease, gastric cancer and gastric mucosa-associated lymphoid tissue (MALT) lymphoma and causes symptoms in a subset of patients with functional dyspepsia. Choice of diagnostic test depends on the clinical context; urea breath tests and endoscopy with biopsy are the major diagnostic tools. Evidence-based indications for eradication of H. pylori infection are well documented. The most widely used and recommended eradication therapy in Australia is triple therapy comprising a proton pump inhibitor, amoxycillin and clarithromycin, usually for 1 week. Effective alternative regimens are available for patients with proven allergy to penicillin. Antimicrobial resistance is the major determinant of the outcome of eradication therapy. Trends in antibiotic resistance need to be monitored locally, but individual patient susceptibility testing is not usually necessary as it rarely guides the choice of therapy. The outcome of treatment should be assessed not less than 4 weeks after therapy. This is usually done with a urea breath test if follow-up endoscopy is not required. When first-line therapy fails, several proven second-line therapies may be used. Repeat first-line therapy and ad hoc regimens should be avoided. Overall cumulative eradication rates should approach 99%.

Adhesion and Invasion of Gastric Mucosa Epithelial Cells by Helicobacter pylori

Helicobacter pylori is the main pathogenic bacterium involved in chronic gastritis and peptic ulcer and a class 1 carcinogen in gastric cancer. Current research focuses on the pathogenicity of H. pylori and the mechanism by which it colonizes the gastric mucosa. An increasing number of in vivo and in vitro studies demonstrate that H. pylori can invade and proliferate in epithelial cells, suggesting that this process might play an important role in disease induction, immune escape and chronic infection. Therefore, to explore the process and mechanism of adhesion and invasion of gastric mucosa epithelial cells by H. pylori is particularly important. This review examines the relevant studies and describes evidence regarding the adhesion to and invasion of gastric mucosa epithelial cells by H. pylori.

Helicobacter pylori infection and polycystic ovary syndrome in adolescent and young adult patients

AIM

Polycystic ovary syndrome (PCOS) is the most common cause of infertility among women of reproductive age. Chronic systemic inflammation has been considered to play a role in the development of PCOS. Helicobacter pylori has been shown to lead to both local gastric and chronic systemic inflammation. In the light of this, the aim of the present study was to investigate a possible link between H. pylori and PCOS.

METHODS

A total of 167 nullipar and single adolescent and young adults (AYA) were recruited for the study: 86 (51.5%) had PCOS and 81 (48.5%) were age-matched controls. The average age was 18.57 ± 2.40 (range, 14-24 years). The recent Amsterdam European Society of Human Reproduction and Embryology/American Society for Reproductive Medicine (ESHRE/ASRM) guidelines including all three of the Rotterdam criteria were used to diagnose PCOS, and enzyme-linked immunosorbent assay kit was used to measure H. pylori IgG.

RESULTS

There was no significant association between the PCOS and non-PCOS groups with regard to the presence of H. pylori IgG (P = 0.924), white blood count or C-reactive protein (P = 0.064; P = 0.383, respectively).

CONCLUSION

The prevalence of H. pylori was not different with regard to PCOS status in AYA. More studies are needed to investigate a possible link between PCOS and H. pylori.

Cancers in Australia in 2010 attributable to modifiable factors: introduction and overview

OBJECTIVE

To describe the approach underpinning a national project to estimate the numbers and proportions of cancers occurring in Australia in 2010 that are attributable to modifiable causal factors.

METHODS

We estimated the population attributable fraction (PAF) (or prevented fraction) of cancers associated with exposure to causal (or preventive) factors using standard formulae. Where possible, we also estimated the potential impact on cancer incidence resulting from changes in prevalence of exposure. Analyses were restricted to factors declared causal by international agencies: tobacco smoke; alcohol; solar radiation; infectious agents; obesity; insufficient physical activity; insufficient intakes of fruits, vegetables and fibre; red and processed meat; menopausal hormone therapy (MHT); oral contraceptive pill (OCP); and insufficient breast feeding. Separately, we estimated numbers of cancers prevented by: aspirin; sunscreen; MHT; and OCP use. We discuss assumptions pertaining to latent periods between exposure and cancer onset, choices of prevalence data and risk estimates, and approaches to sensitivity analyses.

RESULTS

Numbers and population attributable fractions of cancer are presented in accompanying papers.

CONCLUSIONS

This is the first systematic assessment of population attributable fractions of cancer in Australia.

Cancers in Australia in 2010 attributable to infectious agents

OBJECTIVES

To estimate the proportion and numbers of cancers in Australia in 2010 attributable to infectious agents.

METHODS

The population attributable fraction (PAF) and number of cancers caused by hepatitis B and C viruses (HBV, HCV), Helicobacter pylori and human immunodeficiency virus (HIV) were calculated using standard formulae incorporating prevalence of infection in the Australian population, the relative risks associated with that infection and cancer incidence. For cancers with very strong associations to the infectious agent (Epstein-Barr virus [EBV], human papillomavirus [HPV] and HIV/Kaposi's sarcoma herpes virus [KSHV]), calculations were based on viral prevalence in the tumour.

RESULTS

An estimated 3,421 cancers (2.9% of all cancers) in Australia in 2010 were attributable to infections. Infectious agents causing the largest numbers of cancers were HPV (n=1,706), H. pylori (n=793) and HBV/HCV (n=518). Cancer sites with the greatest number of cancers caused by infections were cervix (n=818), stomach (n=694) and liver (n=483). Cancers with highest proportions attributable to infectious agents were Kaposi's sarcoma (100%), cervix (100%), nasopharynx (87%), anus (84%) and vagina (70%).

CONCLUSIONS

Infectious agents cause more than 3,000 cancers annually in Australia.

IMPLICATIONS

Opportunities for cancer prevention through infection control are considerable, even in a 'first world' nation like Australia.

The pathological findings seen in laparoscopic sleeve gastrectomies for weight loss

Sleeve gastrectomy specimens are increasingly common surgical specimens received for examination following bariatric surgery for weight loss. The spectrum of pathological changes seen in these cases is not well documented. Retrospective examination was undertaken of 1463 consecutive sleeve gastrectomy specimens received at Envoi Specialist Pathologists. Most cases showed no pathological changes (80.2%). The most common changes seen were non-specific, non-Helicobacter associated chronic gastritis (7.2%), Helicobacter associated gastritis (6.8%) and benign fundic gland polyps (4.0%). Other, rarer changes were lymphocytic gastritis, autoimmune atrophic gastritis, chronic gastritis with intestinal metaplasia, hyperplastic polyps, pancreatic heterotopia, gastrointestinal stromal tumours (GISTs) and a leiomyoma. A wide range of pathological changes are seen in resection specimens following sleeve gastrectomies for weight loss. Many cases will require further treatment or ongoing investigation and surveillance.

Helicobacter pylori infection as a protective factor against multiple sclerosis risk in females

BACKGROUND

In recent years, a relationship between Helicobacter pylori and many disease conditions has been reported, however, studies in its relationship with multiple sclerosis (MS) have had contradictory results.

OBJECTIVE

To determine the association between the H. pylori infection and MS.

METHODS

550 patients with MS were included in the study and were matched by gender and year of birth to 299 controls. Patients were assessed for clinical and demographic parameters. An enzyme immunoassay was used to detect the presence of specific IgG antibodies against H. pylori in the serum sample of both groups.

RESULTS

H. pylori seropositivity was found to be lower in the patients with MS than in controls (16% vs 21%) with the decrease pertaining to females (14% vs 22%, p=0.027) but not males (19% vs 20%, p=1.0). When adjusted for age at onset, year of birth and disease duration, H. pylori seropositive females presented with a lower disability score than seronegative females (p=0.049), while among males the reverse was true (p=0.025). There was no significant association between H. pylori seropositivity and relapse rate.

CONCLUSIONS

Our results could reflect a protective role of H. pylori in the disease development. However, it may be that H. pylori infection is a surrogate marker for the 'hygiene hypothesis', a theory which postulates that early life infections are essential to prime the immune system and thus prevent allergic and autoimmune conditions later in life. The fact that the association between H. pylori seropositivity and MS risk was seen almost exclusively in females requires further investigation.

Prevalence of Helicobacter pylori infection worldwide: a systematic review of studies with national coverage

The systematic assessment of large population-based surveys addressing the prevalence of Helicobacter pylori infection may provide robust evidence for understanding the trends in the exposure to this major risk factor across settings with distinct patterns of gastric cancer variation. Our aim was to describe the prevalence of H. pylori infection in different countries and periods, through systematic review of the literature. We searched PubMed from inception up to September 2013 to identify original studies reporting on the prevalence of H. pylori, and only those evaluating samples with national coverage were included. We identified 37 eligible studies including data for 22 countries. The prevalences were higher in Central/South America and Asia, and at least two-fold higher in countries with high gastric cancer incidence. In most countries presenting data for different time periods, the prevalences were usually lower in the most recent surveys. However, there was little variation in settings where prevalences were already low. Among countries with high prevalence of H. pylori infection there is an ample scope for reducing its burden in the next decades, whereas further declines in settings with already low prevalences will require more intensive efforts.

Review article: Associations between Helicobacter pylori and obesity--an ecological study

BACKGROUND

There is emerging debate over the effect of Helicobacter pylori infection on body mass index (BMI). A recent study demonstrated that individuals who underwent H. pylori eradication developed significant weight gain as compared to subjects with untreated H. pylori colonisation.

AIM

To elucidate the association between H. pylori colonisation and the prevalence of overweight and obesity in developed countries.

METHODS

The literature was searched for publications reporting data on H. pylori prevalence rates and obesity prevalence rates. Studies selected reported H. pylori prevalence in random population samples with sample sizes of more than 100 subjects in developed countries (GDP >25,000 US$/person/year). Corresponding BMI distributions for corresponding countries and regions were identified. Nonparametric tests were used to compare the association between H. pylori and overweight and obesity rates.

RESULTS

Forty-nine studies with data from 10 European countries, Japan, the US and Australia were identified. The mean H. pylori rate was 44.1% (range 17-75%), the mean rates for obesity and overweight were 46.6 (± 16)% and 14.2 (± 8.9)%. The rate of obesity and overweight were inversely and significantly (r = 0.29, P < 0.001) correlated with the prevalence of H. pylori infection.

CONCLUSIONS

There is an inverse correlation between H. pylori prevalence and rate of overweight/obesity in countries of the developed world. Thus, the gradual decrease of the H. pylori colonisation that has been observed in recent decades (or factors associated with decrease of) could be causally related to the obesity endemic observed in the Western world.

Helicobacter pylori antibody patterns in Germany: a cross-sectional population study

BACKGROUND

Helicobacter pylori infection that is usually acquired in childhood and lasts for lifetime is mostly asymptomatic but associated with severe gastrointestinal disease including cancer. During chronic infection, the gastric mucosa is histologically changing. This forces H. pylori to permanent adaptation in its gastric habitat by expression of different proteins which might be reflected in distinctive antibody patterns.

METHODS

To characterize dynamics of the immune response to H. pylori we analysed 1797 sera of a cross-sectional study representative for the German population (age range 1-82 years) with multiplex serology, a fluorescent bead-based antibody binding assay that allows simultaneous and quantitative detection of antibodies. Fifteen recombinant, affinity-purified H. pylori proteins (UreA, GroEL, Catalase, NapA, CagA, CagM, Cagδ, HP0231, VacA, HpaA, Cad, HyuA, Omp, HcpC and HP0305) were used as antigens.

RESULTS

H. pylori seroprevalence (positivity for at least three antigens) was 48% and increased with age from 12% in children <15 years to 69% in females and 90% in males >65 years. Prevalences were highest (>83%) for Omp, VacA and GroEL. For 11 proteins, seroprevalence was higher in males than females (P < 0.05) from age 55 onwards. For all antigens, the median prevalence increase per age decade was stronger in males (8.4%, range 3.8-12.9%) than females (6.1%, range 3.4-10.8%). However, among seropositives the median number of antigens recognized increased from children <15 years to individuals >65 years stronger in females (P = 0.02). Antibody reactivities to GroEL, HyuA, CagM, Catalase, NapA and UreA also increased stronger in females (average 1.7-fold/decade, SD 0.5) than in males (1.5-fold/decade, SD 0.4).

CONCLUSION

H. pylori antibody response accumulates qualitatively and quantitatively with age. This may reflect a lifelong stimulation of the immune response by chronically active infection.

Comparison of Brazilian Plants Used to Treat Gastritis on the Oxidative Burst of Helicobacter pylori-Stimulated Neutrophil

Ten Brazilian medicinal plants used to treat gastritis and ulcers were carefully selected on the basis of ethnopharmacological importance and antiulcerogenic activity previously described. The antioxidant activity of the methanolic extracts was determined in analysis conditions that simulate a real biological activity on inhibition of the oxidative burst induced in neutrophils using Helicobacter pylori as activator, by a luminol-amplified chemiluminescence assay. The extracts, at low concentration (5 μg/mL), exhibited a large variation in inhibitory effects of H. pylori-induced oxidative burst ranging from 48% inhibition to inactive, but all extracts, excluding Byrsonima intermedia, had inhibitory activity over 80% at the concentration of 100 μg/mL. The total suppressive antioxidant capacity measured as the effective concentration, which represents the extract concentration producing 50% inhibition of the chemiluminescence induced by H. pylori, varies from 27.2 to 56.8 μg/mL and was in the following order: Qualea parviflora > Qualea multiflora > Alchornea triplinervia > Qualea grandiflora > Anacardium humile > Davilla elliptica > Mouriri pusa > Byrsonima basiloba > Alchornea glandulosa > Byrsonima intermedia. The main groups of compounds in tested extracts are presented. Differences in the phytochemical profile, quantitatively and qualitatively, of these plants can explain and justify their protective effect on the gastric mucosa caused by the neutrophil-generated ROS that occurs when H. pylori displays its evasion mechanisms.

A role for altered phagosome maturation in the long-term persistence of Helicobacter pylori infection

The vigorous host immune response that is mounted against Helicobacter pylori is unable to eliminate this pathogenic bacterium from its niche in the human gastric mucosa. This results in chronic inflammation, which can develop into gastric or duodenal ulcers in 10% of infected individuals and gastric cancer in 1% of infections. The determinants for these more severe pathologies include host (e.g., high IL-1β expression polymorphisms), bacterial [e.g., cytotoxicity-associated gene (cag) pathogenicity island], and environmental (e.g., dietary nitrites) factors. However, it is the failure of host immune effector cells to eliminate H. pylori that underlies its persistence and the subsequent H. pylori-associated disease. Here we discuss the mechanisms used by H. pylori to survive the host immune response and, in particular, the role played by altered phagosome maturation.

The association between Barrett's esophagus and Helicobacter pylori infection: a meta-analysis

OBJECTIVE

The effect of Helicobacter pylori on Barrett's esophagus is poorly understood. We conducted a meta-analysis to summarize the existing literature examining the effect that H. pylori has on Barrett's esophagus.

DESIGN

 We performed a comprehensive search to identify studies pertaining to the association between H. pylori and Barrett's esophagus. We conducted meta-regression analyses to identify sources of variation in the effect of H. pylori on Barrett's esophagus.

RESULTS

 Our analysis included a total of 49 studies that examined the effect of H. pylori on Barrett's esophagus and seven studies that examined the effect of cag A positivity on Barrett's esophagus. Overall, H. pylori, and even more so cag A, tended to be protective for Barrett's esophagus in most studies; however, there was obvious heterogeneity across studies. The effect of H. pylori on Barrett's esophagus varied by geographic location and in the presence of selection and information biases. Only four studies were found without obvious selection and information bias, and these showed a protective effect of H. pylori on Barrett's esophagus (Relative risk = 0.46 [95% CI: 0.35, 0.60]).

CONCLUSIONS

 Estimates for the effect of H. pylori on Barrett's esophagus were heterogeneous across studies. We identified selection and information bias as potential sources of this heterogeneity. Few studies without obvious selection and information bias have been conducted to examine the effect of H. pylori on Barrett's esophagus, but in these, H. pylori infection is associated with a reduced risk of Barrett's esophagus.

Prevalence and determinants of Helicobacter pylori sero-positivity in the Australian adult community

BACKGROUND AND AIM

  To estimate the sero-prevalence of Helicobacter Pylori infection in the Australian adult population and identify determinants.

METHODS

  We analyzed serum samples and questionnaire data from 1355 community controls who participated in a nationwide case-control study of esophageal cancer in Australia between 2002 and 2005. We estimated the prevalence ratio and 95% confidence interval using log binomial regression models.

RESULTS

  The age and sex standardized sero-prevalence of H. pylori was 15.5%. The prevalence of infection varied significantly with age, ranging from 5% (< 40 years) to 32% (≥ 70 years). H. pylori infection was significantly higher among those born overseas (prevalence ratio [PR] 1.63; 95% confidence interval [CI] 1.34-1.98) compared with those born in Australia or New Zealand. H. pylori sero-prevalence was 23% higher among participants living in the lowest quartile of socio-economic areas (PR 0.77; 95%CI 0.59-0.99 for Q4 compared with Q1). H pylori serostatus was significantly inversely associated with university education (PR 0.56; 95%CI 0.38-0.83), frequent reflux symptoms (PR 0.62; 95%CI 0.42-0.91), use of proton pump inhibitor (PR 0.69; 95%CI 0.48-0.98) and use of medications for gut spasms (PR 0.48; 95%CI 0.25-0.93). H. pylori serostatus was not associated with body mass index, smoking, alcohol or physical activity.

CONCLUSIONS

  The prevalence of H. pylori infection in Australian adults is lower than other developed countries. H. pylori infection is most common among those living in the areas of socio-economic disadvantage or who were born overseas.

Detection of Helicobacteraceae in intestinal biopsies of children with Crohn's disease

BACKGROUND

Given that members of Helicobacteraceae family colonize the intestinal mucus layer, it has been hypothesized that they may play a role in Crohn's disease. This study investigated the presence of Helicobacteraceae DNA in biopsies collected from children with Crohn's disease and controls.

MATERIALS AND METHODS

The presence of Helicobacteraceae DNA was investigated in intestinal biopsies collected from 179 children undergoing colonoscopy (Crohn's disease n = 77, controls n = 102) using a Helicobacteraceae-specific PCR.

RESULTS

Members of the Helicobacteraceae were detected in 32/77 children with Crohn's disease (41.5%) and 23/102 controls (22.5%). Statistical analysis showed the prevalence of Helicobacteraceae detected in patients to be significantly higher than that in controls (p = .0062). Analysis of non-pylori Helicobacteraceae showed that their prevalence was also significantly higher in patients than in controls (p = .04). Helicobacter pylori was detected in 14.0% of the biopsies across all groups. Given that all children tested were negative for gastric H. pylori, this was a surprising finding. Phylogenetic analysis of H. pylori sequences detected in the biopsies showed that the H. pylori strains identified in the patients did not group with gastric H. pylori included in the analysis, but rather with other H. pylori strains detected in the intestine, gall bladder, and liver.

CONCLUSIONS

The higher prevalence of Helicobacteraceae DNA in Crohn's disease patients would suggest that members of this family may be involved in this disease. In addition, phylogenetic analysis of H. pylori strains showed that extragastric sequences clustered together, indicating that different H. pylori strains may adapt to colonize extragastric niches.

Association of Helicobacter pylori infection with reduced risk for esophageal cancer is independent of environmental and genetic modifiers

BACKGROUND & AIMS

Infection with Helicobacter pylori is associated with reduced risk of esophageal adenocarcinoma (EAC), but it is not clear whether this reduction is modified by genotype, other host characteristics, or environmental factors. Furthermore, little is known about the association between H pylori and adenocarcinomas of the esophagogastric junction (EGJAC) or squamous cell carcinomas (ESCC). We sought to measure the association between H pylori infection and esophageal cancer and identify potential modifiers.

METHODS

In an Australian, population-based, case-control study, we compared the prevalence of H pylori seropositivity and single nucleotide polymorphisms in interleukin (IL)-1B (-31, -511) and tumor necrosis factor (TNF)-alpha (-308, -238) among 260 EAC, 298 EGJAC, and 208 ESCC patients and 1346 controls. To estimate relative risks, we calculated odds ratios (OR) and 95% confidence intervals (CI) using multivariable logistic regression in the entire sample and within strata of phenotypic and genotypic risk factors.

RESULTS

H pylori infection was associated with significantly reduced risks of EAC (OR, 0.45; 95% CI: 0.30-0.67) and EGJAC (OR, 0.41; 95% CI: 0.27-0.60) but not ESCC (OR, 1.04; 95% CI: 0.71-1.50). For each cancer subtype, risks were of similar magnitude across strata of reflux frequency and smoking status. We found no evidence that polymorphisms in IL-1B or TNF-alpha modified the association between H pylori and EAC or EGJAC.

CONCLUSIONS

H pylori infection is inversely associated with risks of EAC and EGJAC (but not ESCC); the reduction in risk is similar across subgroups of potential modifiers.

Prevalence of Helicobacter pylori positivity in patients undergoing percutaneous coronary intervention

BACKGROUND

The adverse effect of haemorrhagic complications after percutaneous coronary intervention (PCI) on outcome is well established with Helicobacter pylori infection known to be an important precipitant of peptic ulcer disease in patients receiving non-steroidal anti-inflammatory drug therapy. The prevalence of H. pylori positivity in patients undergoing PCI and receiving subsequent antiplatelet therapy is unknown.

AIMS

We sought to determine the prevalence and features associated with H. pylori positivity in patients undergoing PCI.

METHODS

All patients undergoing PCI between August 2008 and April 2009 were identified and assessed for H. pylori positivity with serological status determined by using a commercially supplied enzyme-linked immunosorbent assay.

RESULTS

A total of 245 patients undergoing PCI during the study period had samples obtained for H. pylori serology. Of these, 91 were positive for H. pylori serology (37%) and 148 were negative (60%) with six samples being equivocal (3%). Of those patients positive for H. pylori, 75% were on agents at admission known to promote or precipitate gastrointestinal haemorrhage. Patients positive for H. pylori tended to be older, with increased creatinine and more likely to be receiving proton pump inhibitor therapy.

CONCLUSIONS

In an unselected cohort of patients undergoing PCI in a single centre, we detected a prevalence of H. pylori positivity in 37% of patients; this denotes a potentially treatable precipitant of haemorrhage in a considerable portion of patients receiving dual antiplatelet therapy after PCI. Further prospective study is required to determine if the presence of H. pylori positivity is associated with adverse events in terms of gastrointestinal and cardiac outcomes.

Exact confidence limits for prevalence of a disease with an imperfect diagnostic test

Estimation of prevalence of disease, including construction of confidence intervals, is essential in surveys for screening as well as in monitoring disease status. In most analyses of survey data it is implicitly assumed that the diagnostic test has a sensitivity and specificity of 100%. However, this assumption is invalid in most cases. Furthermore, asymptotic methods using the normal distribution as an approximation of the true sampling distribution may not preserve the desired nominal confidence level. Here we proposed exact two-sided confidence intervals for the prevalence of disease, taking into account sensitivity and specificity of the diagnostic test. We illustrated the advantage of the methods with results of an extensive simulation study and real-life examples.

Epidemiology of Helicobacter pylori infection and gastric cancer in Asia

In Asia, the prevalence of Helicobacter pylori (H. pylori) infection varies markedly in different countries. Higher prevalence rates are found in developing Asian countries while lower rates have been reported in more industrialized and developed countries. Within a country, the seroprevalence rates may vary between distinct geographic regions. H. pylori infection is an important etiological factor for the occurrence of non-cardia gastric adenocarcinoma. The incidence rate of gastric adenocarcinoma in Asia tends to mirror the seroprevalence rate of H. pylori infection; however, there are populations with high seroprevalence rates of H. pylori infection that paradoxically have low incidence rates of gastric adenocarcinoma. These diverse clinical outcomes are related to bacterial virulence factors, concomitant environmental factors, host susceptibility and immune response. This review summarizes the current epidemiology of H. pylori infection in Asia and analyzes these data in the context of gastric cancer epidemiology.

The epidemiology of Helicobacter pylori and public health implications

This article presents a review of the literature on the epidemiology and public health implications of Helicobacter pylori infection published from April 2008 through to March 2009. The authors used MeSH terms "Helicobacter infections epidemiology,""Helicobacter infections prevention and control" to search multiple databases (PubMed, Embase, Cochrane, Cochrane Library, EBMR, BIOSIS), and independently searched PubMed using the term "Helicobacter" with "Epidemiology,""Transmission,""Prevalence" or "Environment." Articles without topical relevance were excluded. Two additional papers known to the authors were added. The identified literature is summarized by subtopic: reviews; prevalence; incidence; transmission; risk factors; and public health policy.

Differences in peptic ulcer between the East and the West

PUD affects both the East and the West. The magnitude of the problem, however, varies within these regions. The study of peptic ulcer epidemiology is impeded by the paucity of general population-based data, invasiveness of diagnostic tests, and variable access to testing facilities. As such, direct comparisons of PUD epidemiology between the East and the West are difficult. The prevalence rates of H pylori are highly variable and depend greatly on the local sanitation conditions. The use of NSAIDs and aspirin is ubiquitous and increasing especially for the antiplatelet activity of aspirin in the prophylaxis of cardiovascular events. There is evidence that pharmacogenetics play a role in susceptibility to the ulcerogenic properties of NSAIDs. The prevalence of PUD parallels the risk factors, but emerging in both the East and the West is idiopathic PUD, now a substantial proportion of ulcers in areas of declining H pylori infection. Genetic polymorphisms affect the efficacy of treatment using PPIs. Local H pylori resistance rates also influence the eradication success rates.