Unexpected decrease with age of Helicobacter pylori seroprevalence among Swedish blood donors

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.

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.

The epidemiology of Helicobacter pylori infection in Europe and the impact of lifestyle on its natural evolution toward stomach cancer after infection: A systematic review

BACKGROUND

Helicobacter pylori is a recognized cause of stomach cancer, but only a fraction of infected subjects develop cancer. This systematic review 1, summarizes the prevalence of infection with this bacterium in Europe; and 2, reviews the possible impact of particular lifestyles in progression from infection to stomach cancer.

MATERIALS AND METHODS

A systematic literature search was conducted in two databases by two independent investigators. Studies describing prevalence of infection among European healthy adult populations and worldwide studies analyzing the impact of lifestyle factors in association with H. pylori on stomach cancer risk were included.

RESULTS

Variable H. pylori infection prevalence was observed depending on region and study period. The lowest infection prevalences were found in Northern Europe, while the highest were in Eastern and Southern Europe, up to 84% in Portugal and Poland. Studies on smoking, salt, and meat consumption demonstrated increased risks of developing stomach cancer among H. pylori-infected individuals, while studies relating the intake of fruit, vegetables, and vitamins demonstrated decreased risks, but the levels of significance differed importantly between studies. No significant interaction could be found for alcohol consumption or physical activity.

CONCLUSIONS

Recent data showed remaining high H. pylori infection rates in several European regions. This systematic review suggests that a number of correctable lifestyle factors could impact the disease progression toward H. pylori-associated stomach cancer. However, additional research is required to determine the potential role of targeted interventions in reducing stomach cancer development after H. pylori infection.

Review article: the prevalence of Helicobacter pylori and the incidence of gastric cancer across Europe

BACKGROUND

There is little up-to-date review evidence on the prevalence of Helicobacter pylori across Europe.

AIM

To establish regional and national patterns in H. pylori prevalence across Europe. Secondly, to establish trends over time in H. pylori prevalence and gastric cancer incidence and, thirdly, to report on the relationship between H. pylori prevalence and age group across Europe.

METHODS

A review of H. pylori prevalence from unselected surveys of adult or general populations across 35 European countries and four European regions since 1990. Secondly, an analysis of trends over time in H. pylori prevalence and in gastric cancer incidence from cancer registry data.

RESULTS

Helicobacter pylori prevalence was lower in northern and western Europe than in eastern and southern Europe (P < 0.001). In 11 of 12 European studies that reported on trends, there were sharp reductions in H. pylori prevalence (mean annual reduction = 3.1%). The mean annual reduction in the incidence of gastric cancer across Europe from 1993 to 2007 was 2.1% with little variation regionally across Europe (north 2.2%, west 2.3%, east 1.9% and south 2.0%). Sharp increases in age-related prevalence of H. pylori often levelled off for middle age groups of about 50 years onwards, especially in areas with high prevalence.

CONCLUSIONS

This review shows that H. pylori prevalence is much higher in less affluent regions of Europe and that age-related increases in prevalence are confined to younger age groups in some areas. There were sharp reductions in both H. pylori prevalence and gastric cancer incidence throughout Europe.

Review article: the global emergence of Helicobacter pylori antibiotic resistance

BACKGROUND

Helicobacter pylori is one of the most prevalent global pathogens and can lead to gastrointestinal disease including peptic ulcers, gastric marginal zone lymphoma and gastric carcinoma.

AIM

To review recent trends in H. pylori antibiotic resistance rates, and to discuss diagnostics and treatment paradigms.

METHODS

A PubMed literature search using the following keywords: Helicobacter pylori, antibiotic resistance, clarithromycin, levofloxacin, metronidazole, prevalence, susceptibility testing.

RESULTS

The prevalence of bacterial antibiotic resistance is regionally variable and appears to be markedly increasing with time in many countries. Concordantly, the antimicrobial eradication rate of H. pylori has been declining globally. In particular, clarithromycin resistance has been rapidly increasing in many countries over the past decade, with rates as high as approximately 30% in Japan and Italy, 50% in China and 40% in Turkey; whereas resistance rates are much lower in Sweden and Taiwan, at approximately 15%; there are limited data in the USA. Other antibiotics show similar trends, although less pronounced.

CONCLUSIONS

Since the choice of empiric therapies should be predicated on accurate information regarding antibiotic resistance rates, there is a critical need for determination of current rates at a local scale, and perhaps in individual patients. Such information would not only guide selection of appropriate empiric antibiotic therapy but also inform the development of better methods to identify H. pylori antibiotic resistance at diagnosis. Patient-specific tailoring of effective antibiotic treatment strategies may lead to reduced treatment failures and less antibiotic resistance.

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.

The prevalence of Helicobacter pylori infection in the Netherlands

BACKGROUNDS

The prevalence of Helicobacter pylori has been declining in the developed countries, as it has the incidence of distal gastric carcinoma. Monitoring this decline and identifying populations not benefiting from this decline is a fit task for public health authorities, with blood donors an obvious source of sera.

MATERIALS AND METHODS

We tested 1550 randomly selected blood donors, spread over 5-10 year age cohorts, from four regions in the southern half of The Netherlands, for the presence of antibodies against H. pylori and the CagA antigen. These donors were drawn from an area comprising 46% of the native Dutch population, but did not include non-European immigrants.

RESULTS

We observed an age specific decline in the mean seroprevalence of H. pylori from 48% for donors born between 1946 and 1935 to 16% for those born between 1987 and 1977. In H. pylori positive donors, the CagA seroprevalence declined from 38% to 14% in the same age cohorts. There were no significant differences between regions in either prevalence.

CONCLUSIONS

Our results are compatible with a persistent age-cohort phenomenon for H. pylori prevalence, with the most pronounced decline of CagA+ strains. Nevertheless, almost one in six of the young native Dutch population remains H. pylori positive, implying that, without specific intervention, this bacterium will remain common over the coming decades.

Risk of gastric cancer and peptic ulcers in relation to ABO blood type: a cohort study

Blood group A was found to be associated with gastric cancer in the 1950s. Strikingly, for peptic ulcers an increased risk has been shown for blood group O. However, previous investigations have generally been poorly conducted and have failed to take a unifying approach to these observations. Using the Scandinavian Donations and Transfusions (referred to as "SCANDAT") database, the authors established a cohort of Swedish and Danish blood donors with known blood type and followed these for the occurrence of gastric cancer and peptic ulcers through December 31, 2002. Cases were ascertained by using nationwide cancer and hospital registers. Altogether, 1,089,022 donors were followed for up to 35 years, during which 688 gastric cancer cases and 5,667 peptic ulcer cases accrued. Poisson regression analyses confirmed an increased risk of gastric cancer among individuals with blood group A (incidence rate ratio = 1.20, 95% confidence interval: 1.02, 1.42) and conversely that peptic ulcer risk was instead highest among those with blood group O. In this large, population-based cohort study, the authors have confirmed the association between blood group A and gastric cancer. In addition, they give further support to the notion that individuals with blood group O have a higher risk of peptic ulcers than those with other blood groups.

Longitudinal analysis of serological responses of adults to Helicobacter pylori antigens

Because Helicobacter pylori persist for decades in the human stomach, the aim of this study was to examine the long-term course of H. pylori-specific serum immunoglobulin G (IgG) responses with respect to subclass and antigenic target. We studied paired serum samples obtained in 1973 and in 1994 in Vammala, Finland, from 64 healthy H. pylori-positive adults and from other healthy control subjects. H. pylori serum immunoglobulin A, IgG, and IgG subclass responses were determined by antigen-specific enzyme-linked immunosorbent assays. H. pylori-specific IgG1 and IgG4 subtype responses from 47 subjects were similar in 1973 and 1994, but not when compared with unrelated persons. H. pylori-specific IgG1:IgG4 ratios among the participants varied >1000-fold; however, 57 (89.1%) of 64 subjects had an IgG1:IgG4 ratio >1.0, consistent with a predominant IgG1 (Th1) response. Furthermore, ratios in individual hosts were stable over the 21-year period (r = 0.56; P < .001). The immune response to heat shock protein HspA was unchanged in 49 (77%) of the 64 subjects tested; of the 15 whose serostatus changed, all seroconverted and were significantly younger than those whose status did not change. These findings indicate that H. pylori-specific antibody responses are host-specific with IgG1:IgG4 ratios stable over 21 years, IgG1 responses predominating, and HspA seroconversion with aging.

Helicobacter pylori infection and Barrett's esophagus: a systematic review and meta-analysis

OBJECTIVES

The majority of distal esophageal adenocarcinomas are believed to arise in patients with Barrett's esophagus (BE). Helicobacter pylori (H. pylori) infection plays an etiological role in gastric carcinogenesis, but any possible role in BE is uncertain. We aimed to explore the possible relationship between H. pylori infection and BE by meta-analysis.

METHODS

Observational studies comparing the prevalence of H. pylori infection in patients with BE and healthy controls conducted in adult populations and published in all languages were identified through MEDLINE, EMBASE, and Cochrane database searches up to week 5, 2008. H. pylori infection had to be confirmed by histology and/or serology and/or RUT and/or culture. Studies were excluded if no raw data for outcomes of interest were available or controls were patients with disease or duplicate publications. Summary effect size was calculated as odds ratio (OR) and 95% confidence intervals (CIs) by the random-effects model using Review Manager 4.2.8.

RESULTS

Of 519 citations identified, a total of 12 case-control studies compared the prevalence of H. pylori infection in BE (n=550) and controls (9 studies included controls with normal endoscopy and 3 studies used healthy blood donors as control, n=2,979). There was no significant difference in the overall prevalence of H. pylori infection between BE and controls (42.9% vs. 43.9%, OR=0.74, 95% CI 0.40-1.37, P=0.34), but with significant heterogeneity. Subgroup analysis showed that the prevalence of H. pylori infection was significantly lower in BE than in endoscopically normal healthy controls (23.1% vs. 42.7%, OR=0.50, 95% CI 0.27-0.93, P=0.03) with significant heterogeneity observed between studies. The heterogeneity was eliminated by excluding a single Asian outlier study. In contrast, H. pylori infection was significantly increased in BE patients in the three studies using healthy blood donors as "normal controls" (71.2% vs. 48.1%, OR=2.21, 95% CI 1.07-4.55). In BE patients, the prevalence of H. pylori infection was significantly lower in the esophagus than in the stomach (3.3% vs. 24.7%, OR=0.14, 0.03-0.67) in three studies.

CONCLUSIONS

H. pylori infection and BE are inversely related when compared with endoscopically normal controls but not blood donor controls. Limited evidence suggests that there is no clear association between H. pylori infection and BE. To determine more accurately the effect size of H. pylori infection in BE, high quality prospective case-control studies with age-matched, endoscopically normal healthy controls are needed.

A prospective study of Helicobacter pylori in relation to the risk for pancreatic cancer

BACKGROUND

The relationship between Helicobacter pylori infection and pancreatic cancer has been investigated in three previous studies with contradictory results. The aim of the present study was to investigate the association between H. pylori seropositivity and the risk for pancreatic cancer in a nested case-control study within a population based cohort.

METHODS

Selected birth-year cohorts (born 1921-1949) of residents in Malmö, Sweden, were invited to a health screening investigation. A total of 33 346 subjects participated. Cases with pancreatic cancer (n = 87) were matched to controls (n = 263) using age, sex and time for baseline investigation as matching variables. H. pylori serology was analysed in stored serum samples using an enzyme-linked immunosorbent assay. Odds ratios (OR) for pancreatic cancer were calculated with 95% confidence intervals (CI) using logistic regression.

RESULTS

H. pylori seropositivity was not associated with pancreatic cancer in the total cohort (adjusted OR 1.25 (0.75-2.09)). However, a statistically significant association was found in never smokers (OR 3.81 (1.06-13.63) adjusted for alcohol consumption) and a borderline statistically significant association was found in subjects with low alcohol consumption (OR 2.13 (0.97-4.69) adjusted for smoking).

CONCLUSION

We conclude that no association between H. pylori infection and the risk for pancreatic cancer was found in the total cohort. However, in never smokers and in subjects with low risk alcohol consumption, a positive H. pylori serology was associated with an increased risk for pancreatic cancer. These findings should be interpreted cautiously due to the limited number of cases in these subgroups.

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

This review summarizes key results of epidemiologic studies published in peer-reviewed journals between April 2003 and March 2004. The prevalence of H. pylori infection continues to vary strongly between developing countries and developed countries, and according to ethnicity, place of birth and socioeconomic factors among people living in the same country. Intrafamilial spread appears to play a central role in transmission of the infection in both developing and developed countries. The role of H. pylori infection in development of noncardia gastric cancer appears to be even much stronger than previously assumed, whereas the lack of an association with cardia cancer and an inverse association with adenocarcinoma of the esophagus could be confirmed. Suggestions for an inverse association of the infection with atopic diseases have recently received further support, whereas evidence concerning the role of the infection (or its eradication) in GERD and a large variety of other extragastric diseases, including cardiovascular disease, remains inconclusive.