Helicobacter pylori infection in different generations of Hispanics in the San Francisco Bay Area

Racial disparities of gastric cancer in the USA: an overview of epidemiology, global screening guidelines, and targeted screening in a heterogeneous population

Gastric cancer is the fifth most common cancer diagnosis and fourth leading cause of cancer-related death globally. The incidence of gastric cancer in the USA shows significant racial and ethnic disparities with gastric cancer incidence in Korean Americans being over five times higher than in non-Hispanic whites. Since gastric cancer is not common in the USA, there are no current screening guidelines. In countries with higher incidences of gastric cancer, screening guidelines have been implemented for early detection and intervention and this has been associated with a reduction in mortality. Immigrants from high incidence countries develop gastric cancer at lower rates once outside of their country of origin, but continue to be at higher risk for developing gastric cancer. This risk does seem to decrease with subsequent generations. With increasing availability of endoscopy, initiating gastric cancer screening guidelines for high-risk groups can have the potential to improve survival by diagnosing and treating gastric cancer at an earlier stage. This article aims to provide context to gastric cancer epidemiology globally, review risk factors for developing gastric cancer, highlight racial and ethnic disparities in gastric cancer burden in the USA, examine current guidelines that exist in high incidence countries, and suggest future studies examining the efficacy of additional screening in high-risk populations to reduce gastric cancer mortality and disparate burden on ethnic minorities in the USA.

Population-based evaluation of disparities in stomach cancer by nativity among Asian and Hispanic populations in California, 2011-2015

BACKGROUND

Stomach cancer incidence presents significant racial/ethnic disparities among racial/ethnic minority groups in the United States, particularly among Asian and Hispanic immigrant populations. However, population-based evaluation of disparities by nativity has been scarce because of the lack of nativity-specific population denominators, especially for disaggregated Asian subgroups. Population-based stomach cancer incidence and tumor characteristics by detailed race/ethnicity and nativity were examined.

METHODS

Annual age-adjusted incidence rates were calculated by race/ethnicity, sex, and nativity and tumor characteristics, such as stage and anatomic subsite, were evaluated using the 2011-2015 California Cancer Registry data. For Hispanic and Asian populations, nativity-specific population counts were estimated using the US Census and the American Community Survey Public Use Microdata Sample data.

RESULTS

During 2011-2015 in California, 14,198 patients were diagnosed with stomach cancer. Annual age-adjusted incidence rates were higher among foreign-born individuals than their US-born counterparts. The difference was modest among Hispanics (∼1.3-fold) but larger (∼2- to 3-fold) among Chinese, Japanese, and Korean Americans. The highest incidence was observed for foreign-born Korean and Japanese Americans (33 and 33 per 100,000 for men; 15 and 12 per 100,000 for women, respectively). The proportion of localized stage disease was highest among foreign-born Korean Americans (44%); a similar proportion was observed among US-born Korean Americans, although numbers were limited. For other Asians and Hispanics, the localized stage proportion was generally lower among foreign-born than US-born individuals and lowest among foreign-born Japanese Americans (23%).

CONCLUSIONS

Nativity-specific investigation with disaggregated racial/ethnic groups identified substantial stomach cancer disparities among foreign-born immigrant populations.

The burden of stomach cancer mortality by county, race, and ethnicity in the USA, 2000-2019: a systematic analysis of health disparities

Background

There are persistent disparities in stomach cancer mortality among racial-ethnic groups in the USA, but the extent to which these patterns vary geographically is not well understood. This analysis estimated age-standardised mortality for five racial-ethnic groups, in 3110 USA counties over 20 years, to describe spatial-temporal variations in stomach cancer mortality and disparities between racial-ethnic groups.

Methods

Redistribution methods for insufficient cause of death codes and validated small area estimation methods were applied to death registration data from the US National Vital Statistics System and population data from the US National Center for Health Statistics to estimate annual stomach cancer mortality rates. Estimates were stratified by county and racial-ethnic group (non-Latino and non-Hispanic [NL] American Indian or Alaska Native [AIAN], NL Asian or Pacific Islander [Asian], NL Black [Black], Latino or Hispanic [Latino], and NL White [White]) from 2000 to 2019. Estimates were corrected for misreporting of racial-ethnic group on death certificates using published misclassification ratios. We masked (ie, did not display) estimates for county and racial-ethnic group combinations with a mean annual population of less than 1000; thus, we report estimates for 3079 (of 3110) counties for the total population, and 474, 667, 1488, 1478, and 3051 counties for the AIAN, Asian, Black, Latino, and White populations, respectively.

Findings

Between 2000 and 2019, national age-standardised stomach cancer mortality was lowest among the White population in every year. Nationally, stomach cancer mortality declined for all racial-ethnic groups across this time period, with the most rapid declines occurring among the Asian (percent decline 48.3% [45.1-51.1]) and Black populations (42.6% [40.2-44.6]). Mortality among the other racial-ethnic groups declined more moderately, decreasing by 36.7% (35.3-38.1), 35.1% (32.2-37.7), and 31.6% (23.9-38.0) among the White, Latino, and AIAN populations, respectively. Similar patterns were observed at the county level, although with wide geographic variation. In 2019, a majority of counties had higher mortality rates among minoritised racial-ethnic populations compared to the White population: 81.1% (377 of 465 counties with unmasked estimates for both racial-ethnic groups) among the AIAN population, 88.2% (1295 of 1469) among the Latino population, 99.4% (663 of 667) among the Asian population, and 99.9% (1484 of 1486) among the Black population. However, the size of these disparities ranged widely across counties, with the largest range from 0.3 to 17.1 among the AIAN population.

Interpretation

Stomach cancer mortality has decreased substantially across populations and geographies in the USA. However, disparities in stomach cancer mortality among racial-ethnic groups are widespread and have persisted over the last two decades. Local-level data are crucial to understanding the scope of this unequal burden among minoritised groups in the USA.

Funding

National Institute on Minority Health and Health Disparities; National Heart, Lung, and Blood Institute; National Cancer Institute; National Institute on Aging; National Institute of Arthritis and Musculoskeletal and Skin Diseases; Office of Disease Prevention; and Office of Behavioral and Social Sciences Research, National Institutes of Health (contract #75N94019C00016).

Nativity Status is an Important Social Determinant of Health for Hispanic Patients with Gastric Cancer in Texas

BACKGROUND

The U.S. foreign-born population is rapidly increasing, and cancer incidence/mortality rates have been shown to differ by nativity status. Our study aimed to characterize differences in gastric cancer presentation and survival among Hispanic patients in Texas by nativity status.

METHODS

We conducted a retrospective review of the Texas Cancer Registry to identify Hispanic patients diagnosed with gastric adenocarcinoma between 2004 and 2017. Existing indices applied to 2010 census tract-level data were utilized to measure neighborhood socioeconomic status (nSES) and Hispanic enclaves. Nativity status was imputed for patients with missing data. Multivariable Cox proportional hazard models were fit for overall survival adjusted for age, insurance status, diagnosis year, tumor location, stage, grade, reporting source, nativity status, nSES, and Hispanic enclave.

RESULTS

Our study cohort consisted of 6186 patients and 39% were foreign-born. A greater proportion of foreign-born patients were diagnosed at < 45 years old (16% vs. 11%, p < 0.0001) and had metastatic disease at presentation (47% vs. 34%, p < 0.0001). Foreign-born patients were more often uninsured, in the lowest nSES quintile, and the highest (most ethnically distinct) quintile for Hispanic enclave. Stage-specific overall survival was significantly higher among foreign-born patients. In our multivariate model, foreign-born Hispanic patients had improved survival versus US-born (hazard ratio [HR] 0.90, 95% confidence interval [CI] 0.82-0.99).

CONCLUSIONS

The clinical presentation of gastric cancer differs significantly between foreign-born and U.S.-born Hispanic patients. Foreign-born Hispanic patients have improved survival after adjusting for socioeconomic, neighborhood, and clinical factors. Further studies are needed to identify specific causal mechanisms driving the observed survival difference by nativity status.

Disadvantages for non-Hispanic whites in gastric carcinoma survival in Florida

PURPOSE

The prognosis for gastric carcinoma (GC) remains challenging with less than 35% of patients surviving 5 years. GC survival varies greatly by anatomical site, cardia and non-cardia. However, these important differences have not been thoroughly studied in relation to the increasing diversity in US populations such as Florida. In this study we examined, for the first time, the effect of race-ethnicity on risk of death from GC controlling for potential risk factors separately for cardia and non-cardia GCs.

METHODS

Data on GCs diagnosed in Florida from 2005-2016 were obtained from the statewide cancer registry. Age-standardized GC-specific 5-year survival was computed by anatomical site and race-ethnicity. In addition, a competing risk analysis was performed to assess prognostic factors and to estimate subdistribution hazard ratios of death from GC.

RESULTS

Whites had high proportions of cardia GC (43.9%) compared to all racial/ethnic minorities (10.9%, 19.6%, and 13.8% in Blacks, Hispanics, and Asians, respectively; p < .0001). Among 12,302 cases included, there were 7534 deaths from GC and 1179 from other causes. Age standardized GC-specific 5-year survival was significantly lower for Whites (28.0%) compared to Blacks (31.6%), Hispanics (37.6%), and Asians, (39.6%) and significantly lower for cardia GC (25.0%, 95% CI 23.4-26.6) compared to non-cardia GC (37.0%, 95% CI 35.5-38.4). Multivariable competing risk analysis in patients with non-cardia GC showed that Asians (sHR: 0.64, 95% CI 0.51-0.80), Hispanics (sHR 0.71, 95% CI 0.64-0.78), and Blacks (sHR 0.83, 95% CI 0.75-0.92) all had lower risks of death from GC compared to Whites. In patients with cardia GC, only Hispanics had statistically significant lower risk of death from GC than Whites (sHR 0.84, 95% CI 0.74-0.95, p = 0.005).

CONCLUSIONS

The study of racial/ethnic survival disparities in patients with GC in Florida reveals Whites as the most disadvantaged group. Whites are more afflicted by cardia GC, which is associated with higher risk of death than non-cardia GC. However, even within non-cardia GC, Whites had higher risk of death than the other racial-ethnic groups. Commonly assessed survival determinants do not adequately explain these unusual disparities; thus, further investigation is warranted.

Antibiotic Resistance and Therapy for H. pylori Infection in Immigrant Patients Treated in Italy

Background: Helicobacter pylori (H. pylori) infection is the leading cause of both peptic ulcers and gastric tumors, including low-grade MALT-lymphoma and adenocarcinoma. Although it is decreasing in developed countries, H. pylori prevalence remains high in developing areas, mainly due to low socio-economic levels, and the potential consumption of contaminated water. Moreover, a different pattern of primary antibiotic resistance is expected in their H. pylori isolates, potentially affecting the efficacy of standard eradication therapies. Indeed, a previous study showed the eradication rate following triple therapy was distinctly lower in dyspeptic H. pylori infected immigrants living in Italy as compared to Italian patients. Aims: to evaluate the resistance pattern in H. pylori isolates from immigrant patients in Italy, and the success rate of first-line therapy in these patients. Materials and Methods: This retrospective study evaluated data of consecutive immigrant patients, diagnosed with H. pylori infection in a single center (Bologna, Italy) between January 2009 and January 2019. Patients underwent first-line therapy with either sequential or Pylera^® (Allergan USA, Inc. Madison, NJ, USA) therapy. Results: A total of 609 immigrants were diagnosed with H. pylori infection during the study period, but 264 previously received an eradication therapy. Therefore, the study was focused on 294 out of 345 naïve patients with a successful bacterial culture with antibiogram. Latin America immigrants had the highest overall resistance rate. Levofloxacin resistance rate was significantly higher in Latin Americans and Asians as compared with Europeans. Based on resistance patterns, sequential therapy showed a clear decreasing trend in eradication rates. Conclusions: while antibiotic resistance rates are generally increasing worldwide, Pylera^® seems to achieve a good performance as first-line treatment in all naïve foreigner patients, except for Africans.

Prevalence of iron deficiency in 62,685 women of seven race/ethnicity groups: The HEIRS Study

Background

Few cross-sectional studies report iron deficiency (ID) prevalence in women of different race/ethnicity and ages in US or Canada.

Materials and methods

We evaluated screening observations on women who participated between 2001–2003 in a cross-sectional, primary care-based sample of adults ages ≥25 y whose observations were complete: race/ethnicity; age; transferrin saturation; serum ferritin; and HFE p.C282Y and p.H63D alleles. We defined ID using a stringent criterion: combined transferrin saturation <10% and serum ferritin <33.7 pmol/L (<15 μg/L). We compared ID prevalence in women of different race/ethnicity subgrouped by age and determined associations of p.C282Y and p.H63D to ID overall, and to ID in women ages 25–44 y with or without self-reported pregnancy.

Results

These 62,685 women included 27,079 whites, 17,272 blacks, 8,566 Hispanics, 7,615 Asians, 449 Pacific Islanders, 441 Native Americans, and 1,263 participants of other race/ethnicity. Proportions of women with ID were higher in Hispanics and blacks than whites and Asians. Prevalence of ID was significantly greater in women ages 25–54 y of all race/ethnicity groups than women ages ≥55 y of corresponding race/ethnicity. In women ages ≥55 y, ID prevalence did not differ significantly across race/ethnicity. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.

Conclusions

ID prevalence was greater in Hispanic and black than white and Asian women ages 25–54 y. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.

An Updated Approach to Evaluation and Treatment of Helicobacter pylori Infection

Helicobacter pylori is a chronic bacterial infection that can lead to peptic ulcer disease, chronic gastritis, and gastric cancer. Its prevalence in the United States is lower than in most of the world, although specific populations are at particular risk for disease-related complications, including those with lower socioeconomic status and older adults. Since its discovery, there have been advances in H. pylori diagnosis and treatment, which are the focus of this review for general practice. Practice guidelines have expanded the role for treatment, despite traditional management algorithms resulting in diminished effectiveness as a result of increasing antibiotic resistance. In this context, new approaches warrant discussion. As such, this review aims to provide a clinical context and framework for the testing and rational treatment of H. pylori infection consistent with the available evidence.

High-risk symptoms do not predict gastric cancer precursors

BACKGROUND & STUDY AIMS

Gastric intestinal metaplasia (GIM) is the most common precursor of gastric cancer. Our aim is to determine if presenting symptoms predict gastric cancer precursor lesions in a high-risk population.

PATIENT AND METHODS

Consecutive unique patients evaluated by endoscopy for upper gastrointestinal symptoms at the Los Angeles County Hospital between 2010 and 2014 were evaluated. Presenting symptoms were classified as low- or high-risk depending on the procedure indication as coded using the Clinical Outcomes Research Initiative (CORI) system. Endoscopy and histology results were used to classify findings as benign, GIM, high-risk GIM, or malignant. The primary outcome was the proportion of patients with premalignant or malignant gastric findings who had high-risk clinical indications for endoscopy relative to those with benign results.

RESULTS

A total of 3699 patients underwent endoscopy to evaluate upper gastrointestinal symptoms. There were 373 (10.1%) patients with GIM of which 278 had high-risk GIM. One hundred and sixty (4.3%) patients were diagnosed with gastric cancer. High-risk indications for upper endoscopy predicted gastric cancer (OR 1.8 [95% CI 1.3-2.6]) but not GIM (OR 1.0 [0.8-1.3]) or high-risk GIM (OR 0.9 [0.7-1.2]). Hispanic or Asian patients and patients >50 years old were more likely to have GIM, high-risk GIM, and cancer.

CONCLUSIONS

Performance of upper endoscopy for high-risk indications is inadequate to detect GIM and marginal for malignancy. At risk patients should undergo upper endoscopy for both low- and high-risk symptoms. Screening certain populations deserve additional study and may, in fact, be cost-effective.

Ethnic/racial differences in gastrointestinal symptoms and diagnosis associated with the risk of Helicobacter pylori infection in the US

Background

In the US, neither the prevalence nor the gastrointestinal (GI) diagnosis/symptoms associated with Helicobacter pylori (HP) have been examined in different racial/ethnic groups.

Aim

To determine the racial/ethnic differences in HP infection associated with GI diagnoses/symptoms using the Cerner Health Facts^® database.

Methods

This cross-sectional study collected data during the period of 2000–2015 from the following ethnic/racial groups: 8,236,317 white, 2,085,389 black, 426,622 Hispanic, 293,156 Asian Pacific/Islander (APIs), and 89,179 Native American/Alaskan Native (NA/AN) patients aged 21–65 years old; the data were then analyzed. The primary dependent variable was a diagnosis of HP (ICD-9-Clinical Modification/ICD-10 classification). SAS version 9.4 was used for the statistical analysis. The statistical analysis was performed on 11,130,663 patients with GI symptoms, and of these, 152,086 patients were positive for the infection.

Results

Hispanics and NA/ANs had the highest prevalence of HP associated with upper GI symptoms/diagnosis. Nevertheless, blacks and APIs presented the highest relative risk (RR) of HP associated with dyspepsia (RR [95% CI] =11.2 [10.7–11.9] and 14.2 [12.8–15.6]), peptic ulcer (RR =13.8 [13.3–14.5] and 10.7 [9.3–12.3]), and atrophic gastritis (RR =9 [8.5–9.6] and 7.4 [6.4–8.5]), respectively. In all racial/ethnic groups, HP was also associated with inflammatory bowel diseases, liver diseases, and celiac diseases.

Conclusion

Black and API populations had the highest risk of HP associated with upper GI symptoms/diagnosis. Black patients also had the highest risk for HP associated with GI cancer.

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

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

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

A rising trend in the incidence of advanced gastric cancer in young Hispanic men

BACKGROUND

Although the incidence of gastric cancer has been decreasing, recent reports suggest an increased rate in select populations. We sought to evaluate trends in gastric cancer incidence to identify high-risk populations.

METHODS

Gastric cancer incidence rates from 1992 to 2011 were computed with use of the Surveillance, Epidemiology, and End Results (SEER) registry. We evaluated trends in incidence rates by calculating the annual percent change (APC) across three age groups (20-49 years, 50-64 years, and 65 years or older) and four racial/ethnic groups (Hispanics, non-Hispanic whites, blacks, and Asian/Pacific Islanders).

RESULTS

We identified 41,428 patients with gastric cancer. For the entire cohort during the study period, the APC was decreased. When patients were grouped according to sex, the APC was flat or decreased in women regardless of age or race/ethnicity. The APC was also flat or decreased for all men except young Hispanic men (20-49 years), who had an increased APC of nearly 1.6 % (1.55 %, 95 % confidence interval 0.26-2.86 %). Furthermore, young Hispanic men were the only group to have increased incidence of stage IV disease (APC 4.34 %, 95 % confidence interval 2.76-5.94 %) and poorly differentiated tumors (APC 2.08 %, 95 % confidence interval 0.48-3.70 %).

CONCLUSIONS

The APC of the incidence of gastric cancer in young Hispanic men places it among the top cancers with rising incidence in the USA. This is concomitant with increased incidence of advanced disease at presentation. This major public health concern warrants additional research to determine the cause of the increasing incidence in this group.

ACG Clinical Guideline: Treatment of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) infection is a common worldwide infection that is an important cause of peptic ulcer disease and gastric cancer. H. pylori may also have a role in uninvestigated and functional dyspepsia, ulcer risk in patients taking low-dose aspirin or starting therapy with a non-steroidal anti-inflammatory medication, unexplained iron deficiency anemia, and idiopathic thrombocytopenic purpura. While choosing a treatment regimen for H. pylori, patients should be asked about previous antibiotic exposure and this information should be incorporated into the decision-making process. For first-line treatment, clarithromycin triple therapy should be confined to patients with no previous history of macrolide exposure who reside in areas where clarithromycin resistance amongst H. pylori isolates is known to be low. Most patients will be better served by first-line treatment with bismuth quadruple therapy or concomitant therapy consisting of a PPI, clarithromycin, amoxicillin, and metronidazole. When first-line therapy fails, a salvage regimen should avoid antibiotics that were previously used. If a patient received a first-line treatment containing clarithromycin, bismuth quadruple therapy or levofloxacin salvage regimens are the preferred treatment options. If a patient received first-line bismuth quadruple therapy, clarithromycin or levofloxacin-containing salvage regimens are the preferred treatment options. Details regarding the drugs, doses and durations of the recommended and suggested first-line and salvage regimens can be found in the guideline.

Cancer statistics for Hispanics/Latinos, 2015

Cancer is the leading cause of death among Hispanics/Latinos, who represent the largest racial/ethnic minority group in the United States, accounting for 17.4% (55.4 million/318 million) of the total US population in 2014. Every 3 years, the American Cancer Society reports on cancer statistics for Hispanics based on incidence data from the National Cancer Institute, the Centers for Disease Control and Prevention, and the North American Association of Central Cancer Registries and mortality data from the National Center for Health Statistics. Among Hispanics in 2015, there will be an estimated 125,900 new cancer cases diagnosed and 37,800 cancer deaths. For all cancers combined, Hispanics have 20% lower incidence rates and 30% lower death rates compared with non-Hispanic whites (NHWs); however, death rates are slightly higher among Hispanics during adolescence (aged 15-19 years). Hispanic cancer rates vary by country of origin and are generally lowest in Mexicans, with the exception of infection-associated cancers. Liver cancer incidence rates in Hispanic men, which are twice those in NHW men, doubled from 1992 to 2012; however, rates in men aged younger than 50 years declined by 43% since 2003, perhaps a bellwether of future trends for this highly fatal cancer. Variations in cancer risk between Hispanics and NHWs, as well as between subpopulations, are driven by differences in exposure to cancer-causing infectious agents, rates of screening, and lifestyle patterns. Strategies for reducing cancer risk in Hispanic populations include increasing the uptake of preventive services (e.g., screening and vaccination) and targeted interventions to reduce obesity, tobacco use, and alcohol consumption.

Helicobacter pylori: evidence-based review with a focus on immigrant populations

Helicobacter pylori has been causally linked to a number of diseases, including peptic ulcer disease, gastric adenocarcinoma, mucosa-associated lymphoid tissue lymphoma, and dyspepsia. It is the most prevalent bacterial pathogen in humans, and while the overall prevalence in the United States is about 30 %, the distribution is heterogeneous amongst different ethnic groups. Recent immigrants from high prevalence areas such as Korea, Japan, and China bear an increased burden of its disease and complications. There is clear evidence that treatment of H. pylori resolves peptic ulcer disease, and increasing evidence for protection against development of gastric adenocarcinoma. However, H. pylori treatment failure is common and alternative regimens may be necessary. The following case-based review will highlight these issues, including the epidemiology of H. pylori in the immigrant population, an approach to dyspepsia, and the role of H. pylori in gastric adenocarcinoma.

Probiotics for the treatment of Helicobacter pylori infection in children

The combination of a proton pump inhibitor and two antibiotics (clarithromycin plus amoxicillin or metronidazole) has been the recommended first-line therapy since the first guidelines for Helicobacter pylori (H. pylori) infection in children were published. In recent years, the success of eradication therapies has declined, in part due to the development of H. pylori resistant strains. Alternative anti-H. pylori treatments are currently becoming more popular than the traditional eradication methods. Components that may be used either as a monotherapy or, in combination with antimicrobials, resulting in a more effective anti-H. pylori therapy have been investigated in depth by several researchers. One of the potential therapies is probiotic cultures; promising results have been observed in initial studies with numerous probiotic strains. Nevertheless, many questions remain unanswered. In this article, we comprehensively review the possible mechanisms of action of probiotics on H. pylori infection, and present the results of published studies using probiotics as possible agents to control H. pylori infection in children. The effect of the addition of probiotics to the standard H. pylori eradication therapy for the prevention of antibiotic associated side-effects is also discussed.

Race and ethnicity in cancer therapy: what have we learned?

Racial and ethnic disparities in the pathogenesis of common malignancies and outcomes from treatment remain a major health concern. Factors attributed to these disparities include differences in lifestyle, environment, genetics, and tumor biology. As we strive to personalize cancer therapy, it will be imperative that we understand the relative contributions of each factor so that we may apply this knowledge in choosing the best treatment for each individual, regardless of his or her racial or ethnic heritage.

Ethnicity is a strong predictor for Helicobacter pylori infection in young women in a multi-ethnic European city

BACKGROUND AND AIM

At the same time that Helicobacter pylori prevalence is declining in Western countries, immigrants from developing countries with high H. pylori prevalence have settled in Western urban areas. Actual epidemiological data on H. pylori in a migrant community may help in realizing a more selective approach to assess H. pylori-related diseases. We aimed to define H. pylori prevalence as well as risk groups for H. pylori in a cohort of young women living in a multi-ethnic European city.

METHODS

We measured Immunoglobulin G (IgG) anti-H. pylori and CagA-antibodies in serum of pregnant women included in a population-based prospective cohort study, the Generation R study. Information on demographics and socioeconomic status was collected by questionnaires. Chi-square and logistic regression were used.

RESULTS

In total, 3146 (46%) of the 6837 tested women (mean age 29.7 ± 5.3) were H. pylori-positive and 1110 (35%) of them were CagA-positive. The H. pylori prevalence in Dutch women was 24%, which was significantly lower than in non-Dutch women (64%; P < 0.001). In particular, H. pylori positivity was found in 92% of Moroccan (odds ratio 19.2; 95% confidence interval 11.8-32.0), 80% of Cape Verdean (7.6; 5.0-11.5), 81% of Turkish (9.0; 6.7-12.1), 60% of Dutch Antillean (3.3; 2.3-4.7), and 58% of Surinamese women (3.0; 2.3-3.8). Among H. pylori-positive Dutch subjects, 19% were CagA-positive compared with 40% of the non-Dutch subjects (P < 0.001).

CONCLUSIONS

Despite a general trend of declining prevalence in Western countries, H. pylori remains highly prevalent in migrant communities, which may constitute target groups for screening and eradication to prevent H. pylori-related diseases.

Iron status and Helicobacter pylori infection in symptomatic children: an international multi-centered study

Objective

Iron deficiency (ID) and iron deficiency anaemia (IDA) are global major public health problems, particularly in developing countries. Whilst an association between H. pylori infection and ID/IDA has been proposed in the literature, currently there is no consensus. We studied the effects of H. pylori infection on ID/IDA in a cohort of children undergoing upper gastrointestinal endoscopy for upper abdominal pain in two developing and one developed country.

Methods

In total 311 children (mean age 10.7±3.2 years) from Latin America - Belo Horizonte/Brazil (n = 125), Santiago/Chile (n = 105) - and London/UK (n = 81), were studied. Gastric and duodenal biopsies were obtained for evaluation of histology and H. pylori status and blood samples for parameters of ID/IDA.

Results

The prevalence of H. pylori infection was 27.7% being significantly higher (p<0.001) in Latin America (35%) than in UK (7%). Multiple linear regression models revealed H. pylori infection as a significant predictor of low ferritin and haemoglobin concentrations in children from Latin-America. A negative correlation was observed between MCV (r = −0.26; p = 0.01) and MCH (r = −0.27; p = 0.01) values and the degree of antral chronic inflammation, and between MCH and the degree of corpus chronic (r = −0.29, p = 0.008) and active (r = −0.27, p = 0.002) inflammation.

Conclusions

This study demonstrates that H. pylori infection in children influences the serum ferritin and haemoglobin concentrations, markers of early depletion of iron stores and anaemia respectively.

Barrett's esophagus in Latinos undergoing endoscopy for gastroesophageal reflux disease symptoms

Previous studies comparing the prevalence of Barrett's esophagus in Latinos and non-Latino whites are inconsistent. The aim of the study is to compare the prevalence of Barrett's esophagus in Latinos and non-Latino whites and to determine risk factors associated with Barrett's esophagus. Between March 2005 and January 2009, consecutive Latino and non-Latino white patients who underwent endoscopy for primary indication for symptoms of gastroesophageal reflux disease were identified by examining the internal endoscopy database at Los Angeles County + USC Medical Center. Barrett's esophagus was defined by columnar-lined distal esophagus on endoscopy confirmed by intestinal metaplasia on histology. Clinical features and endoscopic findings were retrospectively reviewed. The mean age of the 663 patients was 50 ± 12 years, 30% were male, and 92% were Latino. Compared with non-Latino whites, Latinos had more females (72% vs. 46%; P = 0.0001) and more Helicobacter pylori infection (53% vs. 24%; P = 0.003) but less tobacco use (7% vs. 17%; P = 0.01). Overall, 10% (68/663) of all patients had Barrett's esophagus whereas the prevalence was 10% (62/611) among the Latinos and 12% (6/52) among the non-Latino whites (OR 0.9, 95% CI 0.4-2.1; P = 0.75). One patient in the Latino group had high-grade dysplasia. On multivariate analysis, male gender (AOR 2.3, 95% CI 1.4-4.1; P = 0.002), diabetes (AOR 2.2, 95% CI 1.1-4.5; P = 0.03), and age ≥55 years (AOR 2.2, 95% CI 1.3-3.8; P = 0.006) were independently associated with Barrett's esophagus; Latino ethnicity remained nonsignificant (AOR 1.1, 95% CI 0.4-2.7; P = 0.88). In Latinos undergoing endoscopy for gastroesophageal reflux disease symptoms, the prevalence of Barrett's esophagus was 10%, comparable with non-Latino white controls as well as the prevalence previously reported among Caucasians. In addition to established risk factors, diabetes was associated with Barrett's esophagus.

Cancer statistics for Hispanics/Latinos, 2012

Hispanics/Latinos are the largest and fastest growing major demographic group in the United States, accounting for 16.3% (50.5 million/310 million) of the US population in 2010. In this article, the American Cancer Society updates a previous report on cancer statistics for Hispanics using incidence data from the National Cancer Institute, the Centers for Disease Control and Prevention, and the North American Association of Central Cancer Registries and mortality data from the National Center for Health Statistics. In 2012, an estimated 112,800 new cases of cancer will be diagnosed and 33,200 cancer deaths will occur among Hispanics. In 2009, the most recent year for which actual data are available, cancer surpassed heart disease as the leading cause of death among Hispanics. Among US Hispanics during the past 10 years of available data (2000-2009), cancer incidence rates declined by 1.7% per year among men and 0.3% per year among women, while cancer death rates declined by 2.3% per year in men and 1.4% per year in women. Hispanics have lower incidence and death rates than non-Hispanic whites for all cancers combined and for the 4 most common cancers (breast, prostate, lung and bronchus, and colorectum). However, Hispanics have higher incidence and mortality rates for cancers of the stomach, liver, uterine cervix, and gallbladder, reflecting greater exposure to cancer-causing infectious agents, lower rates of screening for cervical cancer, differences in lifestyle and dietary patterns, and possibly genetic factors. Strategies for reducing cancer risk among Hispanics include increasing utilization of screening and available vaccines, as well as implementing effective interventions to reduce obesity, alcohol consumption, and tobacco use.

A review of cancer in U.S. Hispanic populations

There are compelling reasons to conduct studies of cancer in Hispanics, the fastest growing major demographic group in the United States (from 15% to 30% of the U.S. population by 2050). The genetically admixed Hispanic population coupled with secular trends in environmental exposures and lifestyle/behavioral practices that are associated with immigration and acculturation offer opportunities for elucidating the effects of genetics, environment, and lifestyle on cancer risk and identifying novel risk factors. For example, traditional breast cancer risk factors explain less of the breast cancer risk in Hispanics than in non-Hispanic whites (NHW), and there is a substantially greater proportion of never-smokers with lung cancer in Hispanics than in NHW. Hispanics have higher incidence rates for cancers of the cervix, stomach, liver, and gall bladder than NHW. With respect to these cancers, there are intriguing patterns that warrant study (e.g., depending on country of origin, the five-fold difference in gastric cancer rates for Hispanic men but not Hispanic women). Also, despite a substantially higher incidence rate and increasing secular trend for liver cancer in Hispanics, there have been no studies of Hispanics reported to date. We review the literature and discuss study design options and features that should be considered in future studies.

Gastric cancer incidence among Hispanics in California: patterns by time, nativity, and neighborhood characteristics

BACKGROUND

Better understanding about gastric cancer incidence patterns among Hispanics by birthplace, socioeconomic status (SES), and acculturation can improve preventive strategies and disease models.

METHODS

Incidence rates, rate ratios, and estimated annual percent change (EAPC) in rates of anatomic and histologic subtype-specific gastric cancer were calculated by age, sex, and nativity among Hispanics using California Cancer Registry data from 1988 through 2004. Incidence rates in 1998 to 2002 were compared by neighborhood SES and Hispanic enclave status according to 2000 US Census data.

RESULTS

Incidence rates of diffuse gastric cancer increased from 1988 through 2004 among foreign-born Hispanic men (EAPC: 3.5%, 95% CI: 1.5%-5.5%) and U.S.-born Hispanic women (EAPC: 3.0%, 95% CI: 0.7%-5.3%). During the same time period, incidence rates of intestinal gastric cancer declined significantly and both cardia and noncardia gastric cancer were steady or declined among foreign-born and U.S.-born Hispanic men and women. Noncardia and both intestinal and diffuse gastric cancer were more common in foreign-born than U.S.-born Hispanic men and women, and in those from lower SES, higher enclave neighborhoods. By contrast, among younger and middle-aged Hispanic men, cardia tumors were more common in the U.S.-born than the foreign-born, and in higher SES, lower enclave neighborhoods.

CONCLUSIONS

Varying gastric cancer risk factors among Hispanic subgroups and increasing rates of diffuse gastric cancer in foreign-born Hispanic men and U.S.-born Hispanic women merit further investigation to identify separate disease etiologies.

IMPACT

Age, sex, birthplace, SES, and acculturation modify gastric cancer incidence in Hispanics and should be considered when examining disease risk and prevention.

Helicobacter pylori in First Nations and recent immigrant populations in Canada

The diminishing prevalence of Helicobacter pylori infection among most segments of the Canadian population has led to changes in the etiologies and patterns of associated upper gastrointestinal diseases, including fewer peptic ulcers and their complications. Canadian Aboriginals and recent immigrants are among populations in which the prevalence of H pylori infection remains high and, therefore, the health risks imposed by H pylori remain a significant concern. Population-based strategies for H pylori eradication in groups with a low prevalence of infection are unlikely to be cost effective, but such measures are attractive in groups in which the prevalence rates of infection remain substantial. In addition to a lower prevalence of peptic ulcers and dyspepsia, the public health value of eradication may be particularly important if this leads to a reduction in the prevalence of gastric cancer in high prevalence groups. Therefore The Canadian Helicobacter Study Group held a conference that brought together experts in the field to address these issues, the results of which are reviewed in the present article. Canadians with the highest prevalence of H pylori infection are an appropriate focus for considering the health advantages of eradicating persistent infection. In Canadian communities with a high prevalence of both H pylori and gastric cancer, there remains an opportunity to test the hypothesis that H pylori infection is a treatable risk factor for malignancy.

Does the risk of stomach cancer remain among second-generation immigrants in Sweden?

The observed increased risks of noncardia stomach cancer among foreign-born second-generation immigrants compared to the Swedes suggest that these immigrants were infected by Helicobacter pylori before immigration.

Chronic gastritis associated with Helicobacter pylori in Mexican children: histopathological patterns

The objective of this study was to analyze the histopathological patterns of inflammation, distribution, severity, and degree of gastric mucosa of Helicobacter pylori (Hp)-infected children in Northern Mexico, as well as the correlation between colonization density and inflammation intensity. We carried out a cross-sectional study of gastric biopsies performed on children ranging from 2 to 17 years of age who underwent upper gastrointestinal endoscopy for diverse gastroduodenal disorders. This study includes only children who were found to be Hp carriers, with positive results for tests of Hp antigens in feces and in gastric biopsy studies. We studied 107 patients (age 8.2 ± 3.7 years). In 47.7% of patients, the density of Hp colonization was low; only 21.5% had a marked density. Mononuclear leukocyte infiltration showed a similar distribution. Thirty-seven percent of patients had follicular gastritis. An acute inflammatory response was absent in 65% and mild in 20.6% of patients. When inflammation was present, it was primarily located in the antrum (79%). There were no cases of intestinal metaplasia or atrophy. A link was found between Hp density and age, infiltration by mononuclear cells, the presence of follicular gastritis, and the level of neutrophil infiltration (P  =  0.001). Despite the high rates of Hp infection in the region, the histopathological findings in these children were mild and were limited primarily to the antral mucosa. These data indicate the need to study the behavior of this disease in children in diverse study populations to provide localized prevention and treatment strategies.

Clinical significance of Helicobacter pylori cagA and iceA genotype status

AIM: To study the presence of Helicobacter pylori (H. pylori) virulence factors and clinical outcome in H. pylori infected patients.

METHODS: A prospective analysis of ninety nine H. pylori-positive patients who underwent endoscopy in our Endoscopy suite were included in this study. DNA was isolated from antral biopsy samples and the presence of cagA, iceA, and iceA2 genotypes were determined by polymerase chain reaction and a reverse hybridization technique. Screening for H. pylori infection was performed in all patients using the rapid urease test (CLO-Test).

RESULTS: From a total of 326 patients who underwent endoscopy for upper gastrointestinal symptoms, 99 patients were determined to be H. pylori-positive. Peptic ulceration was seen in 33 patients (33%). The main virulence strain observed in this cohort was the cagA gene isolated in 43 patients. cagA was associated with peptic ulcer pathology in 39.5% (17/43) and in 28% (16/56) of non-ulcer patients. IceA1 was present in 29 patients (29%) and iceA2 in 15 patients (15%). Ulcer pathology was seen in 39% (11/29) of patients with iceA1, while 31% (22/70) had normal findings. The corresponding values for iceA2 were 33% (5/15) and 33% (28/84), respectively.

CONCLUSION: Virulence factors were not common in our cohort. The incidence of factors cagA, iceA1 and iceA2 were very low although variations were noted in different ethnic groups.

Trends in socioeconomic inequalities in cancer mortality in Barcelona: 1992-2003

BACKGROUND

The objective of this study was to assess trends in cancer mortality by educational level in Barcelona from 1992 to 2003.

METHODS

The study population comprised Barcelona inhabitants aged 20 years or older. Data on cancer deaths were supplied by the system of information on mortality. Educational level was obtained from the municipal census. Age-standardized rates by educational level were calculated. We also fitted Poisson regression models to estimate the relative index of inequality (RII) and the Slope Index of Inequalities (SII). All were calculated for each sex and period (1992-1994, 1995-1997, 1998-2000, and 2001-2003).

RESULTS

Cancer mortality was higher in men and women with lower educational level throughout the study period. Less-schooled men had higher mortality by stomach, mouth and pharynx, oesophagus, larynx and lung cancer. In women, there were educational inequalities for cervix uteri, liver and colon cancer. Inequalities of overall and specific types of cancer mortality remained stable in Barcelona; although a slight reduction was observed for some cancers.

CONCLUSION

This study has identified those cancer types presenting the greatest inequalities between men and women in recent years and shown that in Barcelona there is a stable trend in inequalities in the burden of cancer.

Helicobacter pylori infection and related gastrointestinal diseases

Helicobacter pylori has been implicated in the pathogenesis of a number of digestive tract disorders, such as chronic active gastritis, peptic ulceration, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. Disease outcome is dependent on many factors, including bacterial genotype, host physiology and genetics, and environmental factors such as diet. Researchers continue to explore the complexities of H. pylori infection, seeking to explain why some individuals have asymptomatic infection, whereas others experience clinical disease. The importance of treating H. pylori infection in patients with gastrointestinal problems has been confirmed in recent years, with clinical trials showing that cure of infection can prevent duodenal ulcer and, to a lesser extent, gastric ulcer recurrence; cure early stage mucosa-associated lymphoid tissue lymphoma; and reduce the chances of developing gastric cancer in high-risk individuals.

Proof of an association between Helicobacter pylori and idiopathic thrombocytopenic purpura in Latin America

BACKGROUND

Association between Helicobacter pylori and idiopathic thrombocytopenic purpura (ITP) has been found in Japan and in some European countries. It has also been shown that eradication of H. pylori can increase platelet counts in patients with ITP. The aims of this study were to determine the prevalence of H. pylori infection in patients with ITP in Colombia, and the effect of bacterial eradication on their platelet counts.

MATERIALS AND METHODS

Between December 1998 and April 2006, a total of 32 patients diagnosed with ITP were included in the study. Controls were age and sex matched.

RESULTS

H. pylori infection in patients with ITP was significantly higher (p = .00006) than in control individuals (90.6% and 43.8%, respectively), as determined by (13)C-urea breath test. A significant association between H. pylori infection and ITP was found (p < .0003), with an odds ratio (OR) of 13.15 (95%CI: 3.24-53.29). Multivariate analysis for the association between H. pylori and ITP showed an OR of 20.44 (95%CI: 3.88-107.49) for women and 19.28 (95%CI: 2.03-183.42) for individuals over 50 years. All 29 H. pylori-positive patients with ITP received eradication treatment. After a median follow up of 12.2 months, 80.8% had a recovery in platelet counts.

CONCLUSIONS

According to these results and others from different countries where H. pylori infection rates are high, patients with ITP should be initially tested for H. pylori status, and if present, infection should be eradicated before initiating a drastic conventional ITP treatment. An algorithm for the study and management of patients with ITP in the post-Helicobacter era is presented.

Gastroenteritis and transmission of Helicobacter pylori infection in households

The mode of transmission of Helicobacter pylori infection is poorly characterized. In northern California, 2,752 household members were tested for H. pylori infection in serum or stool at a baseline visit and 3 months later. Among 1,752 person considered uninfected at baseline, 30 new infections (7 definite, 7 probable, and 16 possible) occurred, for an annual incidence of 7% overall and 21% in children <2 years of age. Exposure to an infected household member with gastroenteritis was associated with a 4.8-fold (95% confidence interval [CI] 1.4-17.1) increased risk for definite or probable new infection, with vomiting a greater risk factor (adjusted odds ratio [AOR] 6.3, CI 1.6-24.5) than diarrhea only (AOR 3.0, p = 0.65). Of probable or definite new infections, 75% were attributable to exposure to an infected person with gastroenteritis. Exposure to an H. pylori-infected person with gastroenteritis, particularly vomiting, markedly increased risk for new infection.

Helicobacter pylori occurrence and transmission: a family affair?

About half of the world's population is estimated to be infected with Helicobacter pylori, a gastric bacterium that contributes to the development of peptic ulcer disease and gastric cancer. H. pylori is more prevalent in low-income areas of the world and social and economic development decreases the prevalence as reflected in comparisons both within and between countries. The infection is typically acquired in early childhood and once established commonly persists throughout life unless treated. Person-to-person transmission within the family appears to be the predominant mode of transmission, particularly from mothers to children and among siblings, indicating that intimate contact is important. The route of transmission is uncertain, but the gastro-oral, oral-oral and faecal-oral routes are likely possibilities. Hence, gastroenteritis may facilitate dissemination of the infection. The community and environment may play additional roles for H. pylori transmission in some (low-income) settings. Furthermore, host and bacterial factors may modify the probabilities of acquisition and persistence of the infection. The understanding of H. pylori occurrence and transmission is of practical importance if future study deems prevention of the infection desirable in some high-prevalence populations. The present paper reviews aspects of H. pylori occurrence and transmission with an emphasis on household factors.

Epidemiology of Helicobacter pylori infection

Differences may occur in the mode of transmission of Helicobacter pylori between developed and developing countries: direct human-to-human contacts have been suggested as the primary route in the former while the fecal-oral route, also, through contaminated water, in the latter. Data on intrafamilial transmission of H. pylori among children continue to be produced. The importance of low socioeconomic conditions on the acquisition of H. pylori infection has been confirmed in a number of population-based studies. Due to the improvement of living standards, the prevalence of the infection has fallen dramatically in many countries. It varies from 8.9 to 72.8% among children from developed and developing countries, respectively, the re-infection rate being also significantly higher in the latter. Conflicting data have been reported on the effect of breastfeeding against H. pylori colonization in infancy as well as on the occupational risk for acquiring H. pylori. This review summarizes recent results from the literature on these topics.

HELICOBACTER PYLORI INFECTION AND TREATMENT OUTCOME IN AN URBAN AUSTRALIAN POPULATION

BACKGROUND

To examine the rate of Helicobacter pylori infection in a group of symptomatic patients using rapid urease test and antral histology and report on their treatment outcomes.

METHODS

From a single-surgeon series in a tertiary teaching hospital, 200 consecutive symptomatic patients undergoing their first diagnostic upper gastrointestinal endoscopy during 2003-2004 were included in this retrospective audit. Campylobacter-like organism (CLO) test results were compared with the results of conventional histological examination plus Giemsa staining. Eradication rates and demographic data were collected.

RESULTS

One hundred and seventy-nine of 200 (89.5%) patients had antral biopsies for histology and for CLOtest. The CLOtest was positive in 31% (56/179) of patients. Thirty-two of 56 (57%) patients had an early-positive CLOtest (<24 h). The remaining 43% (24/56) of patients had a late-positive CLOtest (>24 h). Histological examination of the antral biopsy showed evidence of H. pylori in 28/56 (50%) patients with a positive CLOtest. H. pylori eradication therapy was prescribed in 51/56 (91%) patients with a positive CLOtest. Forty-five of 51 (88%) of these patients had a subsequent urea breath test. Urea breath test was positive in 17/45 (29%) patients after H. pylori eradication therapy was prescribed.

CONCLUSION

Rate of H. pylori in this series of symptomatic patients was 31%. As nearly half of the CLOtests became positive after 24 h, we suggest that the CLOtest should be re-examined 24 h after gastroscopy. Standard antral histology and CLOtest were in agreement in only 50% of cases, suggesting that the CLOtest is a more sensitive test. The failure rate of 29% for initial H. pylori eradication therapy reinforces the need for follow up after treatment.

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori infection

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.