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

The Helicobacter pylori Genome Project: insights into H. pylori population structure from analysis of a worldwide collection of complete genomes

Helicobacter pylori, a dominant member of the gastric microbiota, shares co-evolutionary history with humans. This has led to the development of genetically distinct H. pylori subpopulations associated with the geographic origin of the host and with differential gastric disease risk. Here, we provide insights into H. pylori population structure as a part of the Helicobacter pylori Genome Project (HpGP), a multi-disciplinary initiative aimed at elucidating H. pylori pathogenesis and identifying new therapeutic targets. We collected 1011 well-characterized clinical strains from 50 countries and generated high-quality genome sequences. We analysed core genome diversity and population structure of the HpGP dataset and 255 worldwide reference genomes to outline the ancestral contribution to Eurasian, African, and American populations. We found evidence of substantial contribution of population hpNorthAsia and subpopulation hspUral in Northern European H. pylori. The genomes of H. pylori isolated from northern and southern Indigenous Americans differed in that bacteria isolated in northern Indigenous communities were more similar to North Asian H. pylori while the southern had higher relatedness to hpEastAsia. Notably, we also found a highly clonal yet geographically dispersed North American subpopulation, which is negative for the cag pathogenicity island, and present in 7% of sequenced US genomes. We expect the HpGP dataset and the corresponding strains to become a major asset for H. pylori genomics.

Global Trend on Machine Learning in Helicobacter within One Decade: A Scientometric Study

Purpose

This study aims to create a science map, provide structural analysis, investigate evolution, and identify new trends in Helicobacter pylori (H. pylori) research articles.

Methods

All Helicobacter publications were gathered from the Web of Science (WoS) database from August 2010 to 2021. The data were required for bibliometric analysis. The bibliometric analysis was performed with Bibliometrix R Tool. Bibliometric data were analyzed using the Bibliometrix Biblioshiny R-package software.

Results

A total of 17,413 articles were reviewed and analyzed, with descriptive characteristics of the H. pylori literature included. In journals, 21,102 keywords plus and 20,490 author keywords were reported. These articles were also written by 56,106 different authors, with 262 being single-author articles. Most authors' abstracts, titles, and keywords included "Helicobacter-pylori." Since 2010, the total number of H. pylori-related publications has been decreasing. Gut, PLOS ONE, and Gastroenterology are the most influential H. pylori journals, according to source impact. China, the United States, and Japan are the countries with most affiliations and subjects. In addition, Seoul National University has published the most articles about H. pylori. According to the cloud word plot, the authors' most frequently used keywords are gastric cancer (GC), H. pylori, gastritis, eradication, and inflammation. "Helicobacter pylori" and "infection" have the steepest slopes in terms of the upward trend of words used in articles from 2010 to 2021. Subjects such as GC, intestinal metaplasia, epidemiology, peptic ulcer, eradication, and clarithromycin are included in the diagram's motor theme section, according to strategic diagrams. According to the thematic evolution map, topics such as Helicobacter pylori infection, B-cell lymphoma, CagA, Helicobacter pylori, and infection were largely discussed between 2010 and 2015. From 2016 to 2021, the top topics covered included Helicobacter pylori, H. pylori infection, and infection.

Differences in nutritional status between rural and urban Yucatec Maya children: The importance of early life conditions

Early‐life conditions shape childhood growth and are affected by urbanization and the nutritional transition. To investigate how early‐life conditions (across the “first” and “second” 1000 days) are associated with rural and urban children's nutritional status, we analyzed anthropometric data from Maya children in Yucatan, Mexico. We collected weight, height and triceps skinfold measures, then computed body mass and fat mass indices (BMI/FMI), in a cross‐sectional sample of 6‐year‐olds (urban n = 72, rural n = 66). Demographic, socioeconomic and early‐life variables (birthweight/mode, rural/urban residence, household crowding) were collected by maternal interview. We statistically analyzed rural‐urban differences in demographic, socioeconomic, early‐life, and anthropometric variables, then created linear mixed models to evaluate associations between early‐life variables and child anthropometric outcomes. Two‐way interactions were tested between early‐life variables and child sex, and between early‐life variables and rural‐urban residence. Results showed that rural children were shorter‐statured, with lower overweight/obesity and cesarean delivery rates, compared to urban children. Household crowding was a negative predictor of anthropometric outcomes; the strongest effect was in boys and in urban children. Birthweight positively predicted anthropometric outcomes, especially weight/BMI. Birth mode was positively (not statistically) associated with any anthropometric outcome. Cesarean delivery was more common in boys than in girls, and predicted increased height in urban boys. In conclusion, urbanization and household crowding were the most powerful predictors of Maya 6‐year‐old anthropometry. The negative effects of crowding may disproportionately affect Maya boys versus girls and urban versus rural children. Early‐life conditions shape Maya children's nutritional status both in the “first” and “second” 1000 days.

Helicobacter pylori and Gastric Cancer

Helicobacter pylori is present in approximately one-half of the world's population. There are significant differences in prevalence based on region, age, race/ethnicity, and socioeconomic status. H pylori is the most common cause of infection-related cancers. Studies have demonstrated the relationship between H pylori infection and gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. H pylori has features and enzymatic properties allowing it to survive in the acidic stomach environment, and has specific virulence factors that promote an increased risk of gastric pathology. Eradication of H pylori is first-line therapy for mucosa-associated lymphoid tissue lymphoma and decreases the risk of gastric adenocarcinoma.

Helicobacter Pylori: a comprehensive review for primary care providers

Helicobacter pylori is the most prevalent bacteria infecting humans resulting in a variety of gastrointestinal and extra gastrointestinal complications. Although most of the infected adults are asymptomatic, the prevalence varies in different parts of the world it is higher in Eastern and Southern Europe. Eradication of Helicobacter pylori is necessary to prevent precancerous conditions like gastric atrophy, gastric intestinal metaplasia and gastric dysplasia. This comprehensive review addresses briefly on: whom and how to test and treat including recommended first line therapies, salvage therapies, testing for eradication and strategy to be used in primary care clinics.

<p>Seroprevalence of <em>Helicobacter pylori</em> Infection and Associated Factors Among Adult Dyspeptic Patients in Public Health Facilities, Mizan Aman Town, Southwest, Ethiopia: Institutional-Based Cross-Sectional Study</p>

Background

Helicobacter pylori infection is a public health problem associated with chronic gastritis, peptic ulcer, and gastric cancer. It is endemic in developing countries like Ethiopia. This study was aimed to assess seroprevalence of H. pylori infection and associated factors among adults’ dyspeptic patients in public health facilities of Mizan Aman Town, Southwest Ethiopia.

Methods

Cross-sectional study was conducted in public health facilities of Mizan Aman Town, from April 1, 2018, to June 30, 2018. A total of 208 adult dyspeptic patients were included in the study. A structured questionnaire was used to collect data. Serum was tested for anti-H. pylori antibody using a commercial test strip. Data were entered using Epi info 6.04 and exported to SPSS 21 for analysis. Bivariate and multivariate logistic regression was employed and OR with 95% CI was retrieved. P-value of less than 0.05 was considered as statistically significant.

Results

A total of 208 participants were interviewed. The mean age of respondents was 31.70 (SD ±9.123) years. Seroprevalence of H. pylori infection was 89 (42.8%). Presence of domestic animals (AOR = 13.33, 95% CI = (2.203–80.692)), sources of drinking water (AOR = 0.011, 95% CI = (0.001–0.110)), toilet type (AOR = 11.236, 95% CI = (1.921–65.73)), shared beds with siblings (AOR = 7.775, 95% CI = (1.676–36.082)), family size (AOR = 0.015, 95% CI = (0.003, 0.089)), storing and reusing water (AOR =0.014, 95% CI = (0.002–0.103)) and occupational status (AOR = 23.33, 95% CI = (2.034–67.661)) were variables significantly associated with seroprevalence of H. pylori.

Conclusion

Seroprevalence of H. pylori infection is relatively high in Ethiopia. Family size, shared bed, presences of domestic animals, storage and reuse of water, toilet type, sources of drinking water, and occupation were significant factors associated with H. pylori infection. The possible identified modifiable risk factors should be addressed through effective health education.

Helicobacter pylori seroprevalence in Spain: influence of adult and childhood sociodemographic factors

Helicobacter pylori (H. pylori) chronic infection causes severe digestive diseases, including gastric cancer, and certain strains entail a higher risk. Risk factors for this infection are still not fully understood. The aim of this study was to describe the association of adult and childhood sociodemographic factors with the seroprevalence of H. pylori, and with CagA and VacA antigen-specific seropositivity among H. pylori-seropositive individuals in the Spanish adult population. Serum antibody reactivity to H. pylori proteins was evaluated using multiplex serology in 2555 population-based controls enrolled in the MCC-Spain study, a multicase-control study recruiting participants from 2008 to 2013 in different areas of Spain. H. pylori seroprevalence was defined as seropositivity against at least four bacterial proteins. Information on sociodemographics, lifestyles, and environmental exposures was collected through personal interviews. Prevalence ratios and 95% confidence intervals were estimated using Poisson regression models to assess the association of lifetime sociodemographic factors with H. pylori seroprevalence and with seropositivity for CagA and VacA. H. pylori seroprevalence was 87.2%. Seropositivity was statistically significantly higher in men, increased with age, BMI, and number of siblings, and decreased with education and socioeconomic family level at birth. Among H. pylori-seropositive individuals, seropositivity was 53.3% for CagA, 61.4% for VacA, and 38.8% for both CagA and VacA. Ever smokers had lower seroprevalence for CagA and VacA than never smokers. H. pylori seroprevalence among this Spanish adult population was high and one third of the population was seropositive for two well-known markers of gastric cancer risk: CagA and VacA. Sex, age, education, and BMI were associated with H. pylori seroprevalence.

Sequential Helicobacter pylori eradication therapy in Myanmar; a randomized clinical trial of efficacy and tolerability

BACKGROUND AND AIM

There is little published research to examine the best approach to the management of Helicobacter pylori in Myanmar. This study aimed to determine the relative efficacy and tolerability of sequential eradication therapy compared to Myanmar's current recommendation of a concomitant four drug regimen.

METHODS

Patients were screened for H. pylori using monoclonal Stool Antigen Testing (SAT). Those testing positive were randomized 1:1 to receive receive Myanmar's first-line regimen of 14 days of concomitant rabeprazole, clarithromycin, amoxycillin and tinidazole (140 pills, cost US$23) or 10 days of sequential rabeprazole, clarithromycin, amoxycillin and tinidazole (60 pills, cost US$10). Adherence and adverse effects were recorded, and the efficacy of the regimens assessed with repeat SAT.

RESULTS

Of the 1011 patients screened for H. pylori infection, 313 (31%) tested positive. There was no statistical difference in the cure rates of the two regimens in either intention-to-treat: 128/157 (82%; 95% confidence interval (CI): 75-87%) receiving sequential therapy versus 123/156 (79%; 95% CI: 72-85%) receiving concomitant therapy (P = 0.55) or per-protocol analysis: 125/131 (95%; 95% CI: 90-98) receiving sequential therapy versus 121/130 (93%; 95% CI: 87-96) receiving concomitant therapy (P = 0.42). Side effects of therapy were reported in 54/157 (47%) patients taking sequential therapy compared with 62/156 (53%) taking concomitant therapy, but this difference did not reach statistical significance (P = 0.33).

CONCLUSIONS

In this high-burden, resource-poor setting, less expensive sequential therapy was as effective and as well tolerated as the currently recommended concomitant four drug regimen for eradication of H. pylori.

Association between infection with Helicobacter pylori and platelet indices among school-aged children in central Ethiopia: a cross-sectional study

OBJECTIVE

Previous clinical studies in adults from developed countries have implicated Helicobacter pylori infections in the development of thrombocytopenia. However, studies in children, particularly those from low-income countries, are unusually scarce. We examined the association between H. pylori infection and platelet indices in young Ethiopian school children.

DESIGN

Cross-sectional study SETTING: This study was conducted in five elementary schools located in central Ethiopia.

PARTICIPANTS

Blood and stool samples were collected from 971 children across five elementary schools in Ethiopia. H. pylori infection was diagnosed using stool antigen and serum antibody tests, and haematological parameters were measured using an automated haematological analyser. An interviewer-led questionnaire administered to mothers provided information on demographic and lifestyle variables. The independent effects of H. pylori infection on platelet indices were determined using multivariate linear and logistic regressions.

STUDY OUTCOMES

H. pylori-infected children had a lower average platelet count and mean platelet volume than uninfected after adjusting the potential confounders (adjusted mean difference: -20.80×10⁹/L; 95% CI -33.51 to -8.09×10⁹, p=0.001 and adjusted mean difference: -0.236 fL; 95% CI -0.408 to -0.065, p=0.007, respectively). Additionally, H. pylori-infected children had lower red blood cell counts (adjusted mean difference: -0.118×10¹²/L; 95% CI -0.200 to -0.036, p=0.005) compared with non-infected.

CONCLUSION

Our study from a developing country provides further support for an association between H. pylori infections and reduced platelet indices in young Ethiopian school children, after controlling for potential confounders. Further research is needed, particularly longitudinal studies, to establish causality.

Flagellin glycosylation with pseudaminic acid in Campylobacter and Helicobacter: prospects for development of novel therapeutics

Many pathogenic bacteria require flagella-mediated motility to colonise and persist in their hosts. Helicobacter pylori and Campylobacter jejuni are flagellated epsilonproteobacteria associated with several human pathologies, including gastritis, acute diarrhea, gastric carcinoma and neurological disorders. In both species, glycosylation of flagellin with an unusual sugar pseudaminic acid (Pse) plays a crucial role in the biosynthesis of functional flagella, and thereby in bacterial motility and pathogenesis. Pse is found only in pathogenic bacteria. Its biosynthesis via six consecutive enzymatic steps has been extensively studied in H. pylori and C. jejuni. This review highlights the importance of flagella glycosylation and details structural insights into the enzymes in the Pse pathway obtained via a combination of biochemical, crystallographic, and mutagenesis studies of the enzyme-substrate and -inhibitor complexes. It is anticipated that understanding the underlying structural and molecular basis of the catalytic mechanisms of the Pse-synthesising enzymes will pave the way for the development of novel antimicrobials.

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.

Sibling Competition & Growth Tradeoffs. Biological vs. Statistical Significance

Early childhood growth has many downstream effects on future health and reproduction and is an important measure of offspring quality. While a tradeoff between family size and child growth outcomes is theoretically predicted in high-fertility societies, empirical evidence is mixed. This is often attributed to phenotypic variation in parental condition. However, inconsistent study results may also arise because family size confounds the potentially differential effects that older and younger siblings can have on young children's growth. Additionally, inconsistent results might reflect that the biological significance associated with different growth trajectories is poorly understood. This paper addresses these concerns by tracking children's monthly gains in height and weight from weaning to age five in a high fertility Maya community. We predict that: 1) as an aggregate measure family size will not have a major impact on child growth during the post weaning period; 2) competition from young siblings will negatively impact child growth during the post weaning period; 3) however because of their economic value, older siblings will have a negligible effect on young children's growth. Accounting for parental condition, we use linear mixed models to evaluate the effects that family size, younger and older siblings have on children's growth. Congruent with our expectations, it is younger siblings who have the most detrimental effect on children's growth. While we find statistical evidence of a quantity/quality tradeoff effect, the biological significance of these results is negligible in early childhood. Our findings help to resolve why quantity/quality studies have had inconsistent results by showing that sibling competition varies with sibling age composition, not just family size, and that biological significance is distinct from statistical significance.

Intergenerational reduction in Helicobacter pylori prevalence is similar between different ethnic groups living in a Western city

OBJECTIVE

Helicobacter pylori colonisation rates in childhood have declined in Western populations, but it is unknown whether this trend is similar in children of non-Western ethnic backgrounds, born in a Western country. We aimed to identify H. pylori status in children, and determine mother-to-child transmission and risk factors for colonisation.

DESIGN

Antibodies against H. pylori and cytotoxin-associated gene A (CagA) were measured in children participating in a population-based prospective cohort study in Rotterdam, the Netherlands. Information on demographics and characteristics was collected using questionnaires.

RESULTS

We analysed the serum of 4467 children (mean age 6.2 years±0.4 SD) and compared the results with the H. pylori status of their mothers (available for 3185 children). Overall, 438 (10%) children were H. pylori-positive, of whom 142 (32%) were CagA-positive. Independent risk factors for colonisation were: maternal H. pylori positivity (OR 2.12; 95% CI 1.62 to 2.77), non-Dutch ethnicity (OR 2.05; 95% CI 1.54 to 2.73), female gender (OR 1.47; 95% CI 1.20 to 1.80) and lower maternal education level (OR 1.38; 95% CI 1.06 to 1.79). Comparing mothers and children, we found an intergenerational decrease of 76% and 77% for Hp(+)CagA(-) and Hp(+)CagA(+)-strains, respectively, consistent across all nine ethnic groups studied. Male gender, higher maternal educational level and no older siblings, were independently associated with absence of H. pylori.

CONCLUSIONS

Although the highest H. pylori and CagA prevalence was found in children of non-Dutch ethnicities, the decreased colonisation rates were uniform across all ethnic groups, implying the importance of environmental factors in H. pylori transmission in modern cities, independent of ethnicity.

Epidemiology of Helicobacter pylori infection in dyspeptic Ghanaian patients

Introduction

Helicobacter pylori is a gram-negative urease-producing bacterium causally linked with gastritis, peptic ulcer disease and gastric adenocarcinoma. Infection is more frequent and acquired at an earlier age in developing countries compared to European populations. The incidence of Helicobacter pylori infection in dyspeptic Ghanaian patients was 75.4%. However, epidemiological factors associated with infection vary across populations.

Methods

This study used a cross-sectional design to consecutively sample dyspeptic patients at the Endoscopy Unit of the Korle-Bu Teaching Hospital, Accra between 2010 and 2012. The study questionnaire elicited their epidemiological clinical characteristics. Helicobacter pylori infection was confirmed by rapid-urease examination of antral biopsies at upper Gastro-intestinal endoscopy.

Results

The sample population of dyspeptic patients attending the Endoscopy Unit for upper GI endoscopy yielded 242 patients of which 47.5% were females. The age distribution of H. pylori-infection was even across most age – groups, ranging from 69.2% (61 – 70) years to 80% (21 – 30) years. Helicobacter pylori prevalence decreased across areas mapping to the three residential classes in accordance with increasing affluence with rural areas having the highest prevalence. The unemployed and patients in farming had relatively high Helicobacter pylori infection rates of 92.3% and 91.7% respectively.

Conclusion

Helicobacter pylori is endemic in Ghana but the persistently high prevalence across age groups despite significant community anti-microbial use suggests likely re-crudescence or re-infection from multiple sources in a developing country. Socio-cultural factors such as residential class and farming may be facilitating factors for its continued prevalence.

Exposure to Helicobacter pylori infection in early childhood and the risk of allergic disease and atopic sensitization: a longitudinal birth cohort study

Background

An inverse relation between Helicobacter pylori infection and allergic disease has been reported by a range of independent epidemiological studies, but evidence from longitudinal studies is scarce.

Objective

We have investigated the effects of H. pylori infection on the incidence and prevalence of allergic diseases and sensitization in a low-income birth cohort.

Methods

In 2005/2006, a population-based birth cohort was established in Butajira, Ethiopia, and the 1006 singleton babies born were followed up at ages 1, 3, and 5. Symptoms of allergic disease were collected using the ISAAC questionnaire, allergen skin tests performed, and stool samples analysed for H. pylori antigen and geohelminths. Multiple logistic regression was used to determine the independent effects of H. pylori measured at age 3 on the incidence of each outcome between ages 3 and 5 years (in those without the outcome at age 3), controlling for potential confounders, and to additionally assess cross-sectional associations.

Results

A total of 863 children were followed up to age 5. H. pylori infection was found in 25% of the children at both ages 3 and 5, in 21% at age 5 but not 3, and in 17% at age 3 but not at age 5. H. pylori infection at age 3 was significantly associated with a decreased risk of incident eczema between ages 3 and 5 (adjusted OR, 95% CI, 0.31; 0.10–0.94, P = 0.02). Cross-sectionally at age 5, H. pylori infection was inversely associated with skin sensitization (adjusted OR, 95% CI, 0.26; 0.07–0.92, P = 0.02).

Conclusion and clinical relevance

These findings provide further evidence to suggest that early-life exposure to H. pylori may play a protective role in the development of allergy.

Prevalence, incidence and risk factors for Helicobacter pylori infection in a cohort of Portuguese adolescents (EpiTeen)

BACKGROUND

Helicobacter pylori infection is acquired mainly during childhood, but it may occur throughout life. Understanding the determinants of infection at different ages is essential to clarify dynamics of H. pylori related diseases and to design preventive strategies.

AIM

To estimate the prevalence of H. pylori infection at the age of 13 and the incidence after a 3-year follow-up and to identify risk factors for infection.

SUBJECTS AND METHODS

Adolescents born in 1990 were recruited in schools from Porto. Whole-cell anti-H. pylori IgG antibodies were quantified by ELISA. Prevalence ratios (PR) and incidence rate ratios (RR) adjusted for parental education were computed at baseline (n = 1312) and at follow-up (n = 280).

RESULTS

The prevalence was 66.2%, lower in subjects with more educated parents (PR = 0.72, 95%CI: 0.63-0.82), and higher for those having more than one sibling (PR = 1.10, 95%CI: 1.02-1.19) and for smokers (PR = 1.11, 95%CI: 1.02-1.20). The incidence was 4.1/100 person-years. Smoking (RR = 2.35, 95%CI: 1.16-4.75) and type of school (RR = 0.38, 95%CI: 0.16-0.95) were associated with the incidence of infection.

CONCLUSIONS

Prevalence and incidence of H. pylori infection were high, suggesting that gastric cancer will remain an important public health problem in this generation of Portuguese. We identified smoking as a modifiable risk factor for infection.

Epidemiology of Helicobacter pylori infection in six Latin American countries (SWOG Trial S0701)

OBJECTIVE

To investigate the potential determinants of Helicobacter pylori infection between adults 21-65 years old.

METHODS

Data are from the initial screening visit of a randomized clinical trial of three antibiotic regimens to eradicate H. pylori, conducted in seven sites (Santiago-Chile, Túquerres-Colombia, Guanacaste-Costa Rica, Copán-Honduras, Obregón and Tapachula-México, León-Nicaragua). Thousand eight hundred and fifty-nine adults from the general population were screened for H. pylori infection using an urea breath test (UBT) and were interviewed to assess socioeconomic-, demographic-, and symptom-related characteristics. Logistic regression was used to assess the relationship between these characteristics and H. pylori positivity at enrollment.

RESULTS

Among the 1,852 eligible participants for whom a conclusive UBT result was obtained, H. pylori prevalence was 79.4 %, ranging from 70.1 to 84.7 % among the seven centers. Prevalence did not differ by sex (female: 78.4, male: 80.9; p = 0.20) or age (p = 0.08). H. pylori positivity increased with increasing number of siblings (p trend <0.0001). Participants with education beyond 12 years were less likely to be UBT-positive (OR 0.4: 0.3-0.6, compared to participants with 0-6 years of schooling) as were those employed outside the home (OR 0.7: 0.6-1.0). Odds of H. pylori infection increased with the presence of certain living conditions during childhood including having lived in a household with an earth floor (OR 1.8: 1.4-2.4), lack of indoor plumbing (OR 1.3: 1.0-1.8) and crowding (OR 1.4: 1.0-1.8, for having more than two persons per bedroom). Regarding current household conditions, living with more than 3 children in the household (OR 1.7: 1.2-2.5) and crowding (OR 1.8: 1.3-2.3) were associated with H. pylori infection.

CONCLUSIONS

The prevalence of H. pylori in adults was high and differed significantly among the six Latin American countries studied (p < 0.001). Our findings confirm the strong link between poor socioeconomic conditions and H. pylori infection.

Environmental and demographic risk factors for egg allergy in a population-based study of infants

BACKGROUND

Although egg allergy is the most common food allergy in infants and young children, risk factors for egg allergy remain largely unknown. This study examined the relationship between environmental and demographic factors and egg allergy in a population-based infant cohort.

METHODS

In a study of 5276 infants (HealthNuts), infants underwent skin prick testing (SPT) to egg white at 12 months of age. Questionnaire data on relevant exposures were obtained. 699/873 (80%) infants eligible for oral food challenge (detectable wheal on SPT) attended for formal assessment of egg allergy status; 453 had confirmed egg allergy (positive challenge and SPT ≥ 2 mm). Associations between environmental and demographic factors and egg allergy were investigated using multivariable logistic regression.

RESULTS

Children with older siblings and those with a pet dog at home were less likely to develop egg allergy by 1 year of age (adjusted OR [aOR], 0.72; 95% CI, 0.62, 0.83 per sibling; and aOR, 0.72; 95% CI, 0.52, 0.99, respectively). Caesarean section delivery, antibiotic use in infancy, childcare attendance and maternal age were not associated with egg allergy. History of allergic disease in an immediate family member and having parents born in East Asia were strong risk factors for infantile egg allergy (aOR, 1.82; 95% CI, 1.40, 2.36; and aOR, 3.30; 95% CI, 2.45, 4.45, respectively).

CONCLUSIONS

Exposure in the first year of life to siblings and dogs may decrease the risk of subsequent egg allergy. Infants with a family history of allergy and those with parents born in East Asia are at increased risk of egg allergy.

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.

A systematic review and meta-analysis of perinatal variables in relation to the risk of testicular cancer--experiences of the mother

BACKGROUND

We undertook a systematic review and meta-analysis of perinatal variables in relation to testicular cancer risk, with a specific focus upon characteristics of the mother.

METHODS

EMBASE, PubMed, Scopus and Web of Science databases were searched using sensitive search strategies. Meta-analysis was undertaken using STATA 10.

RESULTS

A total of 5865 references were retrieved, of which 67 met the inclusion criteria and contributed data to at least one perinatal analysis. Random effects meta-analysis found maternal bleeding during pregnancy [odds ratio (OR) 1.33, 95% confidence interval (CI) 1.02-1.73], birth order (primiparous vs not, 1.08, 95% CI 1.01-1.16; second vs first, OR 0.94, 95% CI 0.88-0.99; third vs first, OR 0.91, 95% CI 0.83-1.01; fourth vs first, OR 0.80, 95% CI 0.69-0.94) and sibship size (2 vs 1, OR 0.93, 95% CI 0.75-1.15; 3 vs 1, OR 0.89, 95% CI 0.74-1.07; 4 vs 1, OR 0.75, 95% CI 0.62-0.90) to be associated with testicular cancer risk. Meta-analyses that produced summary estimates which indicated no association included maternal age, maternal nausea, maternal hypertension, pre-eclampsia, breech delivery and caesarean section. Meta-regression provided evidence that continent of study is important in the relationship between caesarean section and testicular cancer (P = 0.035), and a meta-analysis restricted to the three studies from the USA was suggestive of association (OR 1.67, 95% CI 1.07-2.56).

CONCLUSIONS

This systematic review and meta-analysis has found evidence for associations of maternal bleeding, birth order, sibship size and possibly caesarean section with risk of testicular cancer.

Epidemiology of Helicobacter pylori infection in asymptomatic children: a prospective population-based study from the Czech Republic. Application of a monoclonal-based antigen-in-stool enzyme immunoassay

BACKGROUND

Acquisition of Helicobacter pylori occurs mainly in childhood and is significantly influenced by geographical variations. The aim of this study is to evaluate the prevalence of H. pylori infection in a population-based sample of asymptomatic children in the Czech Republic. Furthermore, this study aims to identify potential risk factors associated with this infection.

MATERIALS AND METHODS

A prospective, cross-sectional, population-based study was undertaken in 1545 asymptomatic Czech children (aged 0-15 years; male 49.3%). Active H. pylori infection was diagnosed by monoclonal antibody-based antigen-in-stool enzyme immunoassay. Socio-demographic details of each subject were analyzed using a self-administered standardized questionnaire. Multiple regression analysis was performed.

RESULTS

Overall, 7.1% of asymptomatic children were diagnosed with H. pylori infection. Of the infected children, 5.8% lived in the general population. A positive association was found with increasing age, although not with gender. Independent risk factors associated with H. pylori infection in our pediatric population were: the number of children in a household (odds ratio [OR] 4.26; confidence interval [CI] 1.91-9.80); lack of formal education of fathers (OR 0.23; CI 0.18-0.64) and institutionalized children (OR 6.33; CI 2.25-26.50).

CONCLUSIONS

This study of a large cohort of children demonstrated that, independent of gender, H. pylori infection in the Czech Republic is among the lowest reported in Europe. Socioeconomically disadvantaged children, unfortunately, are still at risk of harboring this potentially preventable infection in this low-prevalence region.

Sibship size, Helicobacter pylori infection and chronic atrophic gastritis: a population-based study among 9444 older adults from Germany

BACKGROUND

Early-life social environment has been suggested to play an important role during the development of Helicobacter pylori-related gastric diseases. We aimed to assess the association of sibship size with H. pylori infection and chronic atrophic gastritis (CAG) in a population-based study from Germany.

METHODS

In the baseline examination of ESTHER, a study conducted in Saarland, serological measurements of pepsinogen I and II and H. pylori antibodies were taken in 9444 participants aged 50-74 years. Information on potential risk factors and medical history were obtained by self-administered standardized questionnaire.

RESULTS

A strong dose-response relationship between sibship size and H. pylori seroprevalence was observed (P < 0.01). Adjusted odds ratios (ORs) 95% confidence interval (CI) for H. pylori seropositivity for subjects with 4, 5, 6 and 7 or more siblings compared with subjects without siblings were 1.45 (1.20-1.77), 1.83 (1.50-2.22) and 1.84 (1.47-2.31), respectively. A large sibship size was also associated with an increased risk of CAG with an adjusted OR of 1.42 (1.01-2.01) for 7 or more compared with less than or equal to 2 siblings. This association was attenuated but not entirely eliminated after additional adjustment for H. pylori infection. Notably, a significant association between large sibship size and CAG was also found among H. pylori-negative subjects.

CONCLUSIONS

Our results suggest that large sibship size is associated with increased H. pylori prevalence and CAG risk. The association with CAG risk may be mediated at least in part by H. pylori infection. However, mechanisms other than H. pylori infection may contribute to the 'sibling effect' as well.

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

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