Dynamics of Helicobacter pylori infection in early childhood in a high-risk group living in Germany: loss of infection higher than acquisition

Epidemiological Characteristics of Helicobacter pylori Infection in Children in Northeast Romania

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

Prevalência de infecção por Helicobacter pylori em uma comunidade indígena em São Paulo e fatores associados: estudo transversalPrevalence of Helicobacter pylori infection in an indigenous community in São Paulo and associated factors: cross-sectional study

CONTEXT AND OBJECTIVE:

The prevalence of Helicobacter pylori infection is unevenly distributed among different populations. The aim here was to evaluate the factors associated with Helicobacter pylori infection among children up to five years of age living in a high-risk community.

DESIGN AND SETTING:

Cross-sectional study in an indigenous community of Guarani Mbya ethnicity, Tekoa Ytu and Tekoa Pyau villages, Jaraguá district, city of São Paulo (SP), Brazil.

METHODS:

74 children aged 0.4 to 4.9 years (mean 2.9 ± 1.3 years; median 3.1), and 145 family members (86 siblings, 43 mothers and 16 fathers) were evaluated for Helicobacter pylori infection using the validated 13C-urea breath test. Clinical and demographic data were collected.

RESULTS:

The prevalence was 8.3% among children aged 1-2 years and reached 64.3% among those aged 4-5 years (P = 0.018; overall 31.1%). The prevalence was 76.7% among siblings and 89.8% among parents. There was a negative association with previous use of antibiotics in multivariate analysis adjusted for age (odds ratio, OR: 0.07; 95% confidence interval, CI: 0.01 to 0.66; P = 0.02). The prevalence was higher among males (OR: 1.55), and was associated with maternal infection (OR: 1.81), infection of both parents (OR: 1.5), vomiting (OR: 1.28), intestinal parasitosis (OR: 2.25), previous hospitalization (OR: 0.69) and breastfeeding (OR: 1.87).

CONCLUSIONS:

The prevalence was high among subjects older than three years of age, thus suggesting that the incidence of infection was higher over the first three years of life. Previous use of antibiotics was inversely associated with current Helicobacter pylori infection.

The All-Age Prevalence of Helicobacter pylori Infection and Potential Transmission Routes. A Population-Based Study

BACKGROUND AND AIMS

Previous research on H. pylori epidemiology has mostly focused on adult populations. We have aimed to study H. pylori prevalence in all age groups including children and adolescents and to identify potential routes of transmission.

METHODS

Subjects from all age groups (children 0-11 years, adolescents 12-17 years and adults ≥18 years of age), recruited from both an urban and a rural community in Northern Norway, were invited to provide stool samples for the diagnosis of H. pylori antigen and to fill in a questionnaire (adult and adolescents only) on gastrointestinal symptoms, lifestyle factors and biometric data.

RESULTS

A total of 1 624 (35.3%) of the invited subjects, including 173 (39.3%) of the children, 46 (19.2%) of the adolescents, and 1 416 (36.1%) of the adults, responded to the invitation. H. pylori infection was nearly undetectable (0.6%) among the children, whereas the prevalence increased from 20% in adolescents toward a peak of 45% in the highest age group. Univariate analyses of possible risk factors of H. pylori infection showed significant associations to private well water, the use of outhouse toilet, and having farm animals in childhood, but the associations waned in multivariate analyses.

CONCLUSIONS

In our populations, with apparent high hygienic standards, the transmission of H. pylori infection may start not only in childhood, but also in adolescence, where potential transmission routes may be outdoor toilet use, private well water, and farm animals.

Prevalence and risk factors of Helicobacter pylori infection in asymptomatic Chinese children: a prospective, cross-sectional, population-based study

BACKGROUND

Limited research has been published on current Helicobacter pylori infection rate in asymptomatic children in China.

AIM

To assess current Helicobacter pylori infection rate, distribution characteristics and risk factors in Chinese asymptomatic children.

METHODS

A prospective, cross-sectional, population-based study was performed from 2009 to 2011 in three cities of China. Helicobacter pylori infection was diagnosed by a stool antigen test. Multi-stage cluster random sampling was used to select asymptomatic children including neonates. Socioeconomic details were obtained through a standardised questionnaire.

RESULTS

Among total of 3491 children (0-18 years), the global infection rate was 6.8% and there were no significant differences between genders. Age specific infection rate between regions was significantly different (P < 0.05). The infection rate significantly increased with age (P for trend <0.01). It was low during the newborn (0.6%) to preschool period and was significantly increased in high school students (13.5%) (P < 0.01). Multivariable regression indicated that hand sanitisation, individually served meals, higher education level of mother, above average living space and residence in urban areas were significantly protective against infection (OR 0.749, 0.698, 0.720, 0.838 and 0.770 respectively). Conversely, consuming meals in unsanitised conditions, sharing towels, receiving pre-chewed food from the mother, artificial feeding and family history of gastrointestinal disease were significantly associated with the risk of infection (OR 1.200, 1.965, 2.002, 1.071 and 2.093 respectively).

CONCLUSIONS

Helicobacter pylori infection rate increases with age in Chinese asymptomatic children and is common after 10 years of age. The rate of infection is related to socioeconomic status.

Effect of early and current Helicobacter pylori infection on the risk of anaemia in 6.5-year-old Ethiopian children

BACKGROUND

Epidemiological and clinical studies in high income countries have suggested that Helicobacter pylori (H. pylori) may cause anaemia, but evidence is lacking from low income countries.We examined associations between H. pylori infection in early childhood and anaemia at the age of 6.5 years in an Ethiopian birth cohort.

METHODS

In 2011/12, 856 children (85.1 % of the 1006 original singletons in a population-based birth cohort) were followed up at age six and half. An interviewer-led questionnaire administered to mothers provided information on demographic and lifestyle variables. Haemoglobin level and red cell indices were examined using an automated haematological analyzer (Cell Dyn 1800, Abbott, USA), and stool samples analyzed for H. pylori antigen. The independent effects of H. pylori infection (measured at age 3.5 and 6.5 years) on anaemia, haemoglobin level, and red cell indices (measured at age 6.5 years) were determined using multiple logistic and linear regression.

RESULTS

The prevalence of anemia was 34.8 % (257/739), and the mean (SD) haemoglobin concentration was 11.8 (1.1) gm/dl. Current H. pylori infection at age 6.5 years was positively, though not significantly related to prevalence of anaemia (adjusted OR, 95 % CI, 1.15; 0.69, 1.93, p = 0.59). Any H. pylori infection up to age 6.5 years was significantly associated with an increased risk of anaemia at age 6.5 (adjusted OR, 95 % CI, 1.68; 1.22, 2.32, p = 0.01). A significant reduction in haemoglobin concentration and red cell indices was also observed among children who had any H. pylori infection up to age 6.5 (Hb adjusted β = -0.19, 95 % CI, -0.35 to -0.03, p = 0.01; MCV adjusted β = -2.22, 95 % CI, -3.43 to -1.01, p = 0.01; MCH adjusted β = -0.63, 95 % CI, -1.15 to - 0.12, p = 0.01; and MCHC adjusted β = -0.67, 95 % CI, -1.21 to -0.14, p = 0.01), respectively.

CONCLUSION

This study provides further evidence from a low income country that any H. pylori infection up to age 6.5 is associated with higher prevalence of anaemia, and reduction of haemoglobin level and red cell indices at age 6.5.

High exposure, spontaneous clearance, and low incidence of active Helicobacter pylori infection: the Sorbo San Basile study

BACKGROUND

A decreased incidence of Helicobacter pylori infection has been prospected to occur nowadays.

AIM

To evaluate the exposure to H. pylori, prevalence and incidence of active infection, and related risk factors in the general population.

METHODS

In a small town of Southern Italy (932 inhabitants), 595 (3-97 years) and 157 (12-82 years) subjects among those with no evidence of active H. pylori infection participated at baseline and 10 years later, respectively. A questionnaire was administered. Active H. pylori infection was assessed by (13) C-urea breath test (UBT). Serum VacA and CagA antibodies were determined.

RESULTS

Of 518 subjects who were evaluated by both UBT and serology, 310 (59.8%) were UBT positive, 479 (92.4%) VacA positive, and 369 (71.2%) CagA positive. Subjects UBT negative and serology positive were 169 (32%), ranging 1 (14.2%) to 29 (82.8%) from last to first decades of life. Age, female gender, and people per room were independent risk factors for subjects UBT positive compared to those UBT negative and serology positive. Ten years later, subjects who became UBT positive were four of 157 (0.25% per year) while those who became seropositive for VacA and/or CagA were 17 of 26 (6.5% per year).

CONCLUSIONS

H. pylori infection is highly dynamic with wide range of spontaneous clearance. It is easily cleared in the first decades of life, more recent years, less crowded homes, and males. It disappears and recurs more often than it was previously thought, implying that the current decline in its prevalence is due to real clearance instead of a fall in infection rate.

A possible role of IL-1RN gene polymorphism in the outcome of gastrointestinal diseases associated with H. pylori infection

Objective

To verify whether the variable number of tandem repeat (VNTR) polymorphism in the IL-1RN gene that encodes the interleukin (IL)-1 receptor antagonist (IL-1Ra) plays a role in the outcome of gastrointestinal diseases associated with Helicobacter pylori (H. pylori) infection.

Methods

Patients with normal endoscopy (n = 71), inflammation of the upper gastrointestinal tract only (n = 196), gastric ulcer (n = 28), duodenal ulcer (n = 76), and gastric cancer (n = 19) were studied. H. pylori infection was diagnosed by the urease test, histological examination, and polymerase chain reaction. The IL-1 receptor antagonist gene (IL-1RN intron 2 VNTR) was analyzed by polymerase chain reaction. Gastritis was scored according to the updated Sydney system of classification.

Results

H. pylori infection was an independent risk factor for mild (odds ratio [OR] = 5.53 [95% confidence interval [CI] = 2.63–11.64; P < 0.05]), moderate (OR = 83.93 [95% CI = 29.7–237.18; P < 0.05]) and marked (OR = 47.47 [95% CI = 5.39–418.05; P < 0.05]) gastritis. The carriage of IL-1RN*2/*2 had a significant protective effect of H. pylori infection (OR = 0.31 [95% CI = 0.17–0.57; P < 0.05]). H. pylori infection was identified as an independent risk of inflammation, duodenal ulcer, and gastric ulcer. The carriage of IL-1RN*2/*2 was an independent risk factor for gastric cancer (OR = 5.81 [95% CI = 1.06–31.98; P < 0.05]); nonetheless, the carriage of allele 2 (IL-1RN*2/*2 plus IL-1RN*L/*2) had an independent protective effect on duodenal ulcer (OR = 0.45 [95% CI = 0.22–0.91; P < 0.05]).

Conclusions

Allele 2 of the VNTR IL-1RN polymorphism had a protective effect against duodenal ulcer and H. pylori infection; however, it increased the risk of gastric cancer.

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.

Non-invasive genotyping of Helicobacter pylori cagA, vacA, and hopQ from asymptomatic children

BACKGROUND

Helicobacter pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim is to genotype cagA, hopQ, and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, to avoid selection bias resulting from endoscopy.

METHODS

H. pylori status of 86 asymptomatic children was assessed by (13) C-urea breath test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ, and vacA genes were amplified from stool DNA samples and sequenced.

RESULTS

UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA, and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA-positive children. Of the children's DNA samples, which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA positivity and vacA s1 genotypes (p < 0.0001).

CONCLUSIONS

Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype.

Natural history of Helicobacter pylori infection in childhood: eight-year follow-up cohort study in an urban community in northeast of Brazil

BACKGROUND

Helicobacter pylori infection is acquired predominantly in childhood. There is also evidence that children loss the infection. Therefore, factors that account for children remain infected need to be investigated because once established the infection persists throughout the life unless treated.

METHODS

This study aimed to evaluate the H. pylori infection in children of a low-income community at baseline and 8years later to determine the predictor factors linked to the maintenance, acquisition, and loss of the infection using regression models of generalized estimating equations. H. pylori status was determined by (13) C-urea breath test.

RESULTS

Data from 37.7% (133/353) of the children were available. No difference between the characteristics of the included and nonincluded children was observed. The prevalence of infection increased from 53.4 to 64.7%. Thirty-nine children (29.3%) remained noninfected, 47.4% remained infected, 17.3% became infected, and 6.0% lost the infection. Factors associated with to remain infected compared with to remain noninfected included the age, increased number of children in the household, and the use of well water instead of municipal water. The acquisition of the infection was associated with the male gender.

CONCLUSION

Factors linked to remain and to gain H. pylori infection in a poor region were increased number of children in the household and the male gender. Also, the acquisition rates were higher than the loss rates, which lead to an increase in the infection prevalence with age.

Seroprevalence, correlates and trends of Helicobacter pylori infection in the Israeli population

We examined the prevalence, correlates and trends of H. pylori infection in Israel using residual sera obtained in 2007-2008 from 1466 Jewish subjects aged 0-77 years and 897 Arabs aged 0-19 years, and in 2000-2001 from 627 Jewish and 575 Arab subjects aged 0-19 years. H. pylori IgG antibodies were measured by ELISA. The age-adjusted H. pylori seroprevalence was 45.2% in Jewish participants. Seropositivity increased with age, reaching 60% at age ≥ 50 years and ranged from 24.3% in subjects originating from North America/Western Europe/Australia, to 63.2% in those from Asia/Africa/South America. Among Arabs, H. pylori seroprevalence was 42.1% and reached 65% in adolescents. There was no significant change in seroprevalence between 2000-2001 and 2007-2008. High prevalence of H. pylori was found in Arabs, and in Jews originating from countries of high H. pylori endemicity. These findings are characteristic of countries of diverse ethnic structure and recent immigration.

Serological prevalence of Helicobacter pylori infection in Saxony-Anhalt, Germany, in 2010

Epidemiological studies from different countries have shown a steady decline of the prevalence of Helicobacter pylori infection. In order to investigate the current seroprevalence of H. pylori infection in the area of Magdeburg, a city of the former East Germany, H. pylori antibodies of patients presenting in our emergency wards were analyzed. In total, 2,318 patients (1,181 males and 1,137 females) enrolled between September 2009 and August 2010 were tested for immunoglobulin G (IgG) against H. pylori and anti-CagA antibodies by specific enzyme immunoassay (EIA). Patients with either anti-H. pylori IgG or anti-CagA antibodies were classified as H. pylori positive, whereas the lack of both antibodies led to the assignment of an H. pylori-negative status. The overall seroprevalence of H. pylori infection was 44.4% (n = 1,029 out of 2,318) and did not differ in relation to sex. The proportion of CagA-positive samples was 43.3% of all H. pylori-positive individuals (446 out of 1,029). The seroprevalence showed a birth cohort effect (0 to 20 years of age, 14.6%; 21 to 30 years, 22.4%; 31 to 40 years, 40.6%; 41 to 50 years, 45.5%; 51 to 60 years, 50.8%) up to the age of 60, while it remained between 40.7% and 50.5% for the following decades. Patients younger than 30 years were significantly less H. pylori positive (21.1%) than those older than 30 years of age (47.7%; P < 0.01), whereas CagA status was similar (44.3 versus 43.3%). Notably, young women (<30 years old) had significantly higher CagA positivity (59.3%) than corresponding men (32.5%; P = 0.016). Taken together, seroprevalence of H. pylori infection shows a significant drop in subjects born after 1980 in Saxony-Anhalt but still remains in the range of 40 to 50% in subjects born earlier.

Helicobacter pylori in apparently healthy children aged 0-12 years in urban Kampala, Uganda: a community-based cross sectional survey

Background

Helicobacter pylori is one of the most common causes of bacterial infection in human beings. Studies have showed a high prevalence of Helicobacter pylori among people in low-income countries and colonization early in life. A monoclonal antigen test, performed on faeces, HpSA^®ImmunoCardSTAT, has a high sensitivity, specificity and accuracy and the faecal test can be performed in all ages, also in resource-limited settings. The main objective of this study was to determine the prevalence and factors associated with Helicobacter pylori colonization in apparently healthy children aged 0-12 years in urban Kampala, Uganda.

Method

We tested 427 apparently healthy children, age 0-12 years (211 males, 216 females), in a cross sectional survey for Helicobacter pylori colonization using HpSA ^®ImmunoCardSTAT. A short standardized interview with socio-demographic information and medical history was used to assess risk factors.

Results

The overall prevalence of Helicobacter pylori in the 427 children was 44.3% (189 out of 427). Early colonization was common, 28.7%, in children younger than 1 year of age. The age specific rates were 46.0% in children age 1- < 3 years, 51.7% in children age 3- < 6 years, 54.8% in children age 6- < 9 years and 40.0% in children age 9- < 12 years. There was a significant difference in prevalence by gender; female 38.5% versus male 49.8% and by type of housing; permanent house 38.5% versus semi-permanent house 48.6%. Congestive living and education level of the female caretaker showed a clear trend for a difference in prevalence. Factors independently associated with Helicobacter pylori colonization included: drugs taken last three months, using a pit latrine, sources of drinking water and wealth index.

Conclusion

The prevalence of Helicobacter pylori colonization among urban Ugandan children is high at an early age and increases with age. The impact of Helicobacter pylori colonization on children's health in Uganda needs to be further clarified.

Presence of Helicobacter pylori in a sibling is associated with a long-term increased risk of H. pylori infection in Israeli Arab children

BACKGROUND AND OBJECTIVES

We examined the dynamics of Helicobacter pylori infection between pre-school and school ages and compared the determinants of late acquisition of H. pylori infection with determinants of early and persistent H. pylori infection.

METHODS

ELISA was used to detect H. pylori antigens in stool specimens collected from children at preschool age (3-5 years) and from their mothers and siblings in 2004. The children were tested again for H. pylori at school age (6-9 years) in 2007-2009. Household and socioeconomic characteristics were obtained by interviews.

RESULTS

The prevalence of H. pylori infection increased from 49.7% (95% CI 42.8, 56.7) in 2004 to 58.9% (95% CI 51.8, 65.6) in 2007-2009. Among children tested in both examinations, 69 (49.3%) had persistent infection, 14 (10.0%) were new cases, 56 (40.0%) remained uninfected, and one (0.7%) had lost H. pylori infection. The approximate annual incidence of infection during 2004-2009 was 5%. Sibling's H. pylori positivity at baseline increased the risk for late acquisition of H. pylori infection; adjusted prevalence ratio (PR) 4.62 (95% CI 0.76, 28.23) (p = .09), while maternal education lowered the risk; adjusted PR 0.84 (95% CI 0.69, 1.01) (p = .06). Sibling's H. pylori positivity was the only significant variable associated with early and persistent H. pylori infection in multivariate analysis.

CONCLUSIONS

Most H. pylori infections are acquired at preschool age and transient infection beyond this age is uncommon in this population. Helicobacter pylori-infected siblings are the major reservoir of H. pylori in early and late childhood demonstrating sustained intra-familial transmission of H. pylori.

Antibiotics taken for other illnesses and spontaneous clearance of Helicobacter pylori infection in children

PURPOSE

Factors that determine persistence of untreated Helicobacter pylori (H. pylori) infection in childhood are not well understood. We estimated risk differences for the effect of incidental antibiotic exposure on the probability of a detected clearance at the next test after an initial detected H. pylori infection.

METHODS

The Pasitos Cohort Study (1998-2005) investigated predictors of H. pylori infection in children from El Paso, Texas, and Juarez, Mexico. Children were screened for infection at 6-month target intervals from 6 to 84 months of age, using the 13C-urea breath test corrected for body-size-dependent variation in CO2 production. Exposure was defined as courses of any systemic antibiotic (systemic) or those with anti-H. pylori action (HP-effective) reported for the interval between initial detected infection and next test. Binomial regression models included country of residence, mother's education, adequacy of prenatal care, age at infection, and interval between tests.

RESULTS

Of 205 children with a test result and antibiotic data following a detected infection, the number of children who took > or =1 course in the interval between tests was 74 for systemic and 33 for HP-effective. The proportion testing negative at the next test was 66% for 0 courses, 72% for > or =1 systemic course, and 79% for > or =1 HP-effective course. Adjusted risk differences (95%CI) for apparent clearance, comparing > or =1 to 0 courses were 10% (1-20%) for systemic and 11% (0-21%) for HP-effective.

CONCLUSIONS

Incidental antibiotic exposure appears to influence the duration of childhood H. pylori infection but seems to explain only a small portion of spontaneous clearance.

Decrease in prevalence of Helicobacter pylori infection during a 10-year period in Brazilian children

BACKGROUND

Decreasing prevalence of H pylori infection has been reported in some countries.

AIM

To evaluate the prevalence of Helicobacter pylori infection in a 10-year period in children submitted to upper digestive endoscopy.

METHODS

It was a retrospective observational study. The records of 1,165 endoscopies performed during a 10-year period in a public hospital of the City of São Paulo, SP, Brazil, in patients up to 18-year-old. Only the first endoscopy was considered. Helicobacter pylori infection was defined by the rapid urease test, performed with one fragment of antral mucosa. Chi-square for trend has been estimated to compare Helicobacter pylori prevalence across the period.

RESULTS

The main indication for endoscopy was epigastric pain (47.4%). There were 392 patients with H pylori infection (33.6%), 12.8% being infants, 19.4% toddlers, 28.8% schoolchildren and 46.3% adolescents. Prevalence was 60.47% in the first year of the study and 30.43% in the last. Among the less than 6-year-old patients there was a decrease in infection prevalence from 25% for the 1993--6 period to 14.3% in the 2000--02 period, while among the over 12-year-old patients the decrease was from 55.5% in the first period to 39.6% in the latter. The decrease in H pylori infection prevalence was more intense within patients with epigastric pain, in which prevalence has decreased from 48.2% (92/191) in 1993--6, to 41.9% (65/155) in 1997--9 and 27.7% (57/206) in 2000--02.

CONCLUSION

The study suggests a significant decrease in the prevalence of H pylori infection regarding the studied patients. The trend was mainly observed in the younger age group and in patients with epigastric pain.

Epidemiology of stomach cancer

Despite a major decline in incidence and mortality over several decades, stomach cancer is still the fourth most common cancer and the second most common cause of cancer death in the world. There is a 10-fold variation in incidence between populations at the highest and lowest risk. The incidence is particularly high in East Asia, Eastern Europe, and parts of Central and South America, and it is about twice as high among men than among women. Prognosis is generally rather poor, with 5-year relative survival below 30% in most countries. The best established risk factors for stomach cancer are Helicobacter pylori infection, the by far strongest established risk factor for distal stomach cancer, and male sex, a family history of stomach cancer, and smoking. While some factors related to diet and food preservation, such as high intake of salt-preserved foods and dietary nitrite or low intake of fruit and vegetables, are likely to increase the risk of stomach cancer, the quantitative impact of many dietary factors remains uncertain, partly due to limitations of exposure assessment and control for confounding factors. Future epidemiologic research should pay particular attention to differentiation of stomach cancer epidemiology by subsite, and to exploration of potential interactions between H. pylori infection, genetic, and environmental factors.

Review article: 'true' re-infection of Helicobacter pylori after successful eradication--worldwide annual rates, risk factors and clinical implications

BACKGROUND

The incidence of 'true' re-infection with Helicobacter pylori after successful eradication remains uncertain.

AIM

To determine the worldwide rates, risk factors and clinical implications of 'true' re-infection of Helicobacter pylori. 'True' re-infection of H. pylori is defined as the situation where tests for H. pylori infection, which were negative for 12 months after eradication, become positive again at a later stage.

RESULTS

Thirty six studies were identified through a literature search to be able to produce annual rates of 'true' re-infection, and data from 33 original articles were considered reliable and adequate in the further review. Generally, the reported rates varied from 0% to 23.4% in adults and from 1.9% to 9.6% in children. Most studies from developed countries reported rates of less than 1%, whereas relatively higher rates were reported in most of the developing countries. Small sample sizes included in the studies appeared to be associated with increased re-infection rates. Interfamilial transmission is the major cause of re-infection, although iatrogenic re-infection through contaminated endoscopic equipment has been reported.

CONCLUSION

Helicobacter pylori re-infection is not a concern in a clinical setting, especially in the developed world; however, caution must be exercised in most developing countries.

Helicobacter pylori infection and iron stores: a systematic review and meta-analysis

BACKGROUND AND AIMS

We carried out a systematic literature review and meta-analysis to evaluate the existing evidence on the association between Helicobacter pylori infection and iron stores.

METHODS

Twelve case reports and case series, 19 observational epidemiologic studies and six intervention trials were included in the review.

RESULTS

Although only few studies controlled for multiple potential confounders, most studies reported a positive association, linking between H. pylori and decreased body iron stores in symptomatic and asymptomatic H. pylori-infected subjects. H. pylori infection may be regarded as a risk factor for reduction in body iron stores and also for iron deficiency or iron deficiency anemia, especially in high-risk groups. The results of the meta-analysis of thoroughly designed and analyzed studies revealed an increased risk for iron deficiency anemia; pooled odds ratio (OR) 2.8 (95% confidence interval (CI) 1.9, 4.2) and also for iron deficiency; pooled OR 1.38 (95%CI 1.16-1.65) among H. pylori-infected subjects. The biologic mechanism by which H. pylori induces the alteration in the iron stores is not fully understood, but it seems to involve several pathways, including gastrointestinal blood loss, decrease in the absorption of dietary iron, and enhanced uptake of the iron by the bacterium.

CONCLUSIONS

H. pylori is associated with reduced iron stores. Future research is needed to determine whether this relationship is a causal association and to better understand its biologic mechanism. The impact of anti-H. pylori therapy on improvement of iron stores needs to be further evaluated in large and well-controlled trials.

Correspondence between Helicobacter pylori antibodies and urea breath test results in a US-Mexico birth cohort

The uncertain accuracy of methods for detecting Helicobacter pylori infection in young children complicates research on this infection in early life. The aim of the present report was to describe the correspondence between positive serology and positive urea breath test (UBT) in children followed from age 0 to 24 months in the Pasitos Cohort Study, conducted along the US-Mexico border at El Paso and Juarez. Children were recruited before birth during 1998-2000 and examined at target ages of 6, 12, 18 and 24 months. H. pylori infection was detected using an enzyme immunoassay for serum immunoglobulin G antibodies and the (13)C-urea breath test corrected for age-dependent variation in CO(2) production. Of 472 children, 125 had one or more positive UBT results and 46 had one or more positive serology results. The prevalence of H. pylori infection at target ages of 6, 12, 18 and 24 months was 7%, 14%, 16% and 19%, respectively, by UBT and 8%, 2%, 3% and 3%, respectively, by serology. Few (<1%) of those tested on both tests were positive on both at any age. Among UBT-positive children, 6% were concurrently seropositive and 6% became seropositive later. Because UBT positivity cut points were selected to minimise false positives, these results suggest that H. pylori infection occurred frequently in this cohort, but rarely produced detectable antibodies. For clinical or epidemiological investigations, serology should not be used as the sole method for detecting H. pylori infection in children aged 2 years or less.

Utility of diagnostic tests for detection of Helicobacter pylori in children in northeastern Mexico

BACKGROUND

The presence of Helicobacter pylori in pediatric population has been associated with recurrent abdominal pain (RAP), although this association is unclear. One of the major problems in studying the role of H. pylori in RAP is that methods used to detect the bacteria in children have poor sensitivity and specificity. The aims of the present study were to determine the prevalence of H. pylori in pediatric patients with RAP in northeastern Mexico and to assess the diagnostic utility of invasive tests and serology in this population.

METHODS

A total of 40 patients (mean age, 7.9 years; range 2-16 years; F: M, 0.81), who underwent an endoscopy procedure for RAP, were studied. The presence of H. pylori was assessed using invasive diagnostic tests (culture, rapid urease test, polymerase chain reaction and histology) and one non-invasive test: determination of IgG antibodies. The prevalence of H. pylori in the present group and the diagnostic utility for each test were evaluated.

RESULTS

The prevalence of H. pylori in the present pediatric group with RAP was 12.5-42.5% depending on the criteria of positivity used. The non-invasive methods (serology) had acceptable values in sensitivity and specificity in comparison with invasive tests.

CONCLUSIONS

This is the first report on prevalence of H. pylori in pediatric patients with RAP from the northeastern region of Mexico. The prevalence of H. pylori was low compared with the adult population in the same geographic region. Serology had the best diagnostic utility.

Helicobacter pylori infection in pediatrics

During the last year, epidemiologic studies have shown that spontaneous clearance of Helicobacter pylori infection has a less significant role in countries with high prevalence and, in contrast to adults, there is no male predominance of H. pylori infection in children. Early acquisition of H. pylori may play a role in the development of recurrent abdominal pain in children less than 5 years of age. In this very young age group, the adequate performance of stool antigen test and (13)C urea-breath test demonstrated satisfactory sensitivity and specificity as non-invasive methods to diagnose H. pylori infection. In the current paper, the most relevant pediatric studies on H. pylori infection published between April 2006 and March 2007 are reviewed.

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.

Natural history and symptomatology of Helicobacter pylori in childhood and factors determining the epidemiology of infection

BACKGROUND

High seroprevalence rates for Helicobacter pylori have been reported in developing countries, yet few studies exist determining the pattern of change in the epidemiology of H. pylori infection in children. The knowledge of acquisition and loss rates of H. pylori and the relevance to the sociodemographic properties and the symptomatology of infection may provide clues for lifestyle changes that might protect children from infection, and also, it may provide rationale for eradication, screening, and protection policies. Our aim was to conduct a prospective study to elucidate the outcome, rate of acquisition, and loss of H. pylori infection in a population of healthy children.

METHODS

This study is based on follow-up of 327 healthy Turkish children aged 3 to 12 years. The follow-up was conducted 6 years after the baseline examination. Helicobacter pylori status was determined by C-urea breath test. Children were investigated for sociodemographic variables and several symptoms.

RESULTS

Data from 136 (41%) of 327 children were available. The prevalence of infection increased from 52.9% to 56.6%, mainly increasing in children younger than 10 years. The incidence of H. pylori infection among previously uninfected children was 14%, and the loss rate of infection among previously infected children was 5.5% during the follow-up. Socioeconomic status, household density, and antibiotic use during last 6 months were inversely related to H. pylori prevalence. Children infected with H. pylori were complaining more often of headache but not of abdominal pain or dyspepsia.

CONCLUSIONS

In this study, the acquisition rate of H. pylori infection was 2.5-fold higher than the loss of infection, and the acquisition mostly occurred before 10 years of age. Data regarding acquisition and loss of H. pylori infection are critical for understanding the epidemiology of infection and development of preventive and treatment strategies.

[Helicobacter pylori infection in the child population in Spain: prevalence, related factors and influence on growth]

INTRODUCTION

A causal relationship between Helicobacter pylori infection and the occurrence of digestive diseases in adults and children has been proven. Worldwide, the prevalence of H. pylori varies and it is possibly influenced by differences in the level of development. The goals of this study were a) to ascertain the prevalence of H. pylori infection in the child population in Spain, b) to study several factors related to this infection, and c) to establish its possible influence on growth.

PATIENTS AND METHODS

We performed a descriptive, cross-sectional survey of a representative sample of children aged 1 to 14 years old. The sample consisted of 284 children (prevalence 5 15 %; accuracy 5 4 %; CI > 95 %), selected at random and stratified by age and sex. A pre-coded questionnaire was used for data collection. Diagnosis of H. pylori was established by detection of H. pylori antigen in stools with enzyme immunoassay.

RESULTS

The sample consisted of 144 boys and 140 girls, with a mean age of 6.89 6 4.25 years. The prevalence of H. pylori infection was 15.8 % and progressively increased with age: 1- to 3-year-olds (8.4 %), 4- to 9-year-olds (13.9 %), 10- to 14-year-olds (24 %) (p < 0.05). The prevalence was significantly higher in boys (p < 0.01). Analysis of socio-environmental variables showed a higher H. pylori infection rate in children from families with a low socioeconomic level (p < 0.01), a high rate of overcrowding (p < 0.05), and in immigrants (p < 0.001). The H. pylori infection rate was higher in children with recurrent abdominal pain (p < 0.001) and in those whose parents had suffered from gastroduodenal disease (p < 0.001). H. pylori infection was more frequent in children aged 10 to 14 years old with weight and height percentiles below the 25th percentile (p < 0.05). Comparison of means revealed no significant differences.

CONCLUSIONS

The prevalence of H. pylori infection found in our study was slightly lower than that found in other studies carried out in Spain; our data were more similar to those of industrialized countries. H. pylori infection was linked to age, sex and deprived socioeconomic environments, and was more frequent in children with recurrent abdominal pain and in those whose parents suffered from gastroduodenal disease. H. pylori infection did not seem to negatively affect growth in our child population.

Prevalence of Helicobacter pylori infection in children (south of Iran)

The prevalence of Helicobacter pylori in children ranges from 10% to more than 80%. High prevalence occurs in developing countries, and after colonization it takes an extended period to be eradicated by the immune system. To evaluate the prevalence and age distribution of H. pylori infection in children in Shiraz (a city in the south of Iran), we collected 593 stool samples from children selected randomly from 5 age groups. Infection was determined based on antigen immunoassay in stool using the enzyme-linked immunosorbent assay method. The prevalence rates were 82%, 98%, 88%, 89%, and 57% in age groups of 9 months, and 2, 6, 10, and 15 years, respectively. There were no significant differences between the prevalence of H. pylori infection in the first 4 age groups (P > 0.05), but there was a significant decrease in the 15-year-old group (P < 0.05). The prevalence of H. pylori infection in the south of Iran is very high. The infection begins at infancy and remains high until late childhood.

Age-specific incidence of Helicobacter pylori

BACKGROUND & AIMS

Helicobacter pylori is most likely acquired in childhood, but the incidence of infection has not been determined prospectively by using an appropriate noninvasive test. The aim of this study was to determine the age-specific incidence of Helicobacter pylori infection in children and the risk factors for infection.

METHODS

Three hundred twenty-seven healthy index children between 24 and 48 months of age were enrolled over 15 months. At baseline, the Helicobacter pylori infection status of each index child and his or her older siblings and parents was assessed by using the carbon 13-urea breath test. All noninfected index children were then followed up with an annual carbon 13-urea breath test for 4 years to determine whether they became infected with Helicobacter pylori and, if so, the age at first infection. Information on potential risk factors was collected at baseline and each subsequent visit.

RESULTS

At baseline assessment, 28 of 327 (8.6%) index children were infected with Helicobacter pylori. The mean age of the 28 infected children was 32.78 months (SD, 5.14 months). Over the next 4 years, 279 index children not infected at baseline contributed 970 person-years of follow-up to the study. During this time, 20 children became infected with Helicobacter pylori. The rate of infection per 100 person-years of follow-up was highest in the 2-3-year age group (5.05 per 100 person-years of follow-up (95% confidence interval, 1.64-11.78) and declined progressively as children aged. Only 1 child became infected after 5 years of age. Having an infected mother, an infected older sibling, and delayed weaning from a feeding bottle (ie, after 24 months of age) were all risk factors for infection.

CONCLUSIONS

Children who become infected with Helicobacter pylori are infected at a very young age, and the risk of infection declines rapidly after 5 years of age. These findings have important implications for studies on the mode of transmission of infection.

Helicobacter pylori-specific immune response in maternal serum, cord blood, and human milk among mothers with and without current Helicobacter pylori infection

We assessed the patterns of Helicobacter pylori (H. pylori) specific maternal antibodies in maternal serum, cord blood, and milk, which might play a role in prevention of H. pylori infection because transferred to the infant. Between November 2000 and November 2001, mothers were recruited after delivery of their offspring. H. pylori infection status was determined by 13C-urea breath test (UBT). Specific H. pylori antibody profiles were analysed using commercial H. pylori-specific enzyme-linked immunosorbent assay and Western blots. Among 898 mothers, 23% had a current H. pylori infection. Median H. pylori IgG antibody titers in serum and cord blood of UBT-positive mothers were 23.8 U/mL and 24.0 U/mL, respectively. Whereas prevalences of H. pylori-specific antibodies in serum of UBT-negative mothers were clearly lower than those among UBT-positive mothers, patterns of H. pylori-specific IgA antibodies in milk were similar among UBT-positive and UBT-negative mothers. Neonates born from H. pylori-infected women are provided with large amounts of transplacentally transferred specific IgG H. pylori antibodies. Breast-fed neonates are additionally provided with specific IgA antibodies in human milk. Notably, the latter may also be activated if exposure of the mother to H. pylori might have been long time ago and been cleared in the meantime.

Dynamics of Helicobacter pylori infection in a US-Mexico cohort during the first two years of life

BACKGROUND

The Pasitos Cohort Study has followed children in El Paso, Texas and Ciudad Juarez, Mexico since 1998 to identify determinants of Helicobacter pylori infection. This paper describes patterns of acquisition and elimination of H. pylori infection in 468 children from birth to 24 months.

METHODS

Mothers were recruited during pregnancy at maternal-child clinics; children were targeted for follow-up examinations every 6 months after birth. H. pylori infection was detected using the 13C-urea breath test, corrected for age-dependent variation in CO2 production.

RESULTS

Test results were available for 359, 341, 269, and 215 children around target ages of 6, 12, 18, and 24 months, respectively. The person-time at risk of a first detectable infection was 7742 person-months; 128 first infections were detected, thus the incidence rate was 1.7% per month (95% confidence interval 1.4-2.0%). Rates were similar in boys and girls and on both sides of the border; evidence suggests, however, that this similarity could be due to selection bias. Among children with follow-up after a positive test, 77% tested negative at a later visit.

CONCLUSIONS

The initial acquisition of detectable H. pylori infection occurred at a rate of 20% per year among Pasitos Cohort children from birth to 24 months of age. A key finding, with implications for clinical, community health, and research settings, is that most of these infections did not persist. The transient nature of early H. pylori infection should be considered when designing research or contemplating therapeutic intervention for this age group.

Increase of antigen-presenting cells in the gastric mucosa of Helicobacter pylori-infected children

BACKGROUND

Infection with Helicobacter pylori leads to an increase of T cells in the gastric mucosa of children. In contrast to peripheral blood, where monocytes are the most abundant antigen-presenting cells, CD14+ macrophages are very rare in infected gastric mucosa. We postulated that other types of antigen-presenting cells must be present in infected gastric mucosa.

MATERIAL AND METHODS

Antral biopsies were obtained from 56 children. The cellular expression of major histocompatibility complex (MHC) class II molecules, CD1a/b, and CD23, which are involved in antigen presentation were analyzed by immunohistochemistry. In addition, T cells (CD4, CD8, CD25, and gamma/delta-TCR), B cells (anti-IgM), macrophages (CD14) and granulocytes (CD15) were quantified.

RESULTS

Twenty-eight children were H. pylori-infected. Thirteen children were healthy, 15 had other gastric pathologies. T cells (p<.0001), B cells (p<.0001), CD23+ (p<.0001), and CD1a/b+ (p<.005) cells were significantly increased in the lamina propria of H. pylori-infected children, whereas macrophages were rare without significant differences among the groups. Within the epithelium, CD8+ T lymphocytes predominated clearly over CD4+ cells. H. pylori-negative children had only few MHC class II-positive cells within the gastric epithelium, whereas MHC class II antigens were strongly expressed on epithelial cells (p<.0001) of all H. pylori-infected children.

CONCLUSION

Helicobacter pylori infection leads to an enhanced expression of antigen-presenting molecules together with a parallel rise of T cells in the lamina propria. This may represent an effort of the immune system to optimize local immune responses against H. pylori. We speculate that the epithelium participates in the initiation of a local immune response against H. pylori.

HpSA fecoprevalence in patients suspected to have Helicobacter pylori infection in Istanbul, Turkey

OBJECTIVE

This study aims to investigate the Helicobacter pylori antigen in the stool samples of patients suspected to have H. pylori infection. It also aims to determine the fecoprevalence in different age groups and to look for the relationship between the clinical symptoms seen in patients and the existence of H. pylori. Current information in Turkey is insufficient.

METHODS

The Helicobacter pylori antigen was investigated in the stool samples of 445 patients of whom 148 were in the 2-15 year age group, 96 in the 16-30 year age group, 85 in the 31-40 year age group and 116 in the 41-48 year age group. The main clinical complaints of the patients (stomach pain, heart burn, indigestion, gas, nausea, vomiting, diarrhea, abdominal pain) were recorded.

RESULTS

The Helicobacter pylori antigen was found in 36.6% (163/445) of the patients and in the statistical evaluation made for different age groups, a significant linear relationship was found between age and infection (chi2=14.77, p=0.002).

CONCLUSION

It was found that stomach pain was seen at a higher rate in patients with H. pylori antigen compared to those without it. The difference was highly statistically significant (chi2=117.70, p<0.001, OR=20.36, 95% CI=10.56-39.27).

The incidence of Helicobacter pylori acquisition in children of a Canadian First Nations community and the potential for parent-to-child transmission

BACKGROUND AND AIMS

We have previously reported that Wasagamack, a Canadian First Nations community has a seroprevalence rate of Helicobacter pylori of 95% and a prevalence rate among children aged 0-12 years as measured by stool antigen testing of 56%. We aimed to determine the rate of infection acquisition and possible modes of transmission of childhood Helicobacter pylori infection in this Canadian First Nations community.

METHODS

Children who were previously negative for H. pylori by stool antigen testing in August 1999 were eligible for enrollment in August 2000; 50 (77%) eligible children underwent stool collection. H. pylori stool antigen status was tested using the Premier Platinum HpSA test. Drinking water samples, maternal saliva, breast milk, local berries and flies were tested by three complementary H. pylori-specific PCR assays. Soothers or bottle nipples, collected from 16 children whose H. pylori stool antigen status was determined, were bathed in sterile water and this water was tested by PCR.

RESULTS

Stool was positive for H. pylori in 16% (8/ 50) of children retested. Five had no other siblings infected and three had infected siblings. The mothers of all children infected were positive for H. pylori. The median age of newly infected children was 6 years (range 1-13 years). By PCR, 78% (18/23) mothers' saliva samples, 69% (11/16) soother water samples and 9% (1/11) water samples from infected homes tested positive. All of 24 sequenced PCR-produced DNA fragments from samples showed 99% homology with that from ATCC type strain H. pylori.

CONCLUSIONS

The rate of childhood H. pylori acquisition was 16% over 1 year, and was not dependent on number of siblings infected. The finding of homologous H. pylori DNA in saliva and in soother water suggests the possibility of human to human transmission, particularly via an oral-oral route. Thus, there is the potential for further investigations in this population and other endemic communities that are directed at prevention of infection transmission via this modality.

Helicobacter pylori infection in pediatric population: epidemiology, pathophysiology, and therapy

Helicobacter pylori, one of the most commonly encountered human pathogens, has been recognized in more than half of adults and children with chronic nonspecific gastritis, and nearly all children with peptic ulcer disease demonstrate antral infection with H. pylori. A high prevalence and early colonization of H. pylori infection in childhood was described in developing countries in contrast to developed countries. The current diagnostic methods include histology, microbiological culture, urease activity detection, polymerase chain reaction, and stool antigen detection. The infection often presents with nausea, vomiting, and epigastric pain but may remain asymptomatic. The treatment modality options are multiple; however, the association of a proton-pump inhibitor and two antibiotics for 1 or 2 weeks gives the best eradication rates. Drug resistance is a growing problem in this microorganism and new therapeutic options are currently limited.

Helicobacter pylori infection in pediatrics

A high prevalence and early colonization of Helicobacter pylori infection in childhood was described again this year in developing countries in contrast to developed ones. Upper gastrointestinal endoscopy including gastric biopsies remains the diagnostic gold standard method for this infection. Also noninvasive tests have been studied in children, including serology, 13C-urea breath test and stool antigen test, showing good results in the different age groups as compared to the gold standard. However, the infection often remains asymptomatic in children and the role of this bacterium in gastric manifestations is the subject of conflicting reports. Extra-digestive manifestations are also reported in the course of this infection. The treatment of H. pylori infection is influenced by resistance of the bacteria to the antibiotics used. We suggest that eradication of H. pylori should take place only after susceptibility testing. The association of a proton pump inhibitor and two antibiotics for 1 or 2 weeks gives the best eradication rates. The crucial question to elucidate is whether asymptomatic children should be treated to prevent cancer in the future.

Burden of Helicobacter pylori and H. pylori-related diseases in developed countries: recent developments and future implications

Helicobacter pylori colonizes the gastric mucosa. H. pylori infection is the main cause of peptic ulcer and gastric malignancy. This review gives an overview on the epidemiology of H. pylori infection and H. pylori-associated diseases in the developed world, mainly Europe, and it discusses very recent developments with regard to the prevalence and its future implications for H. pylori-associated diseases.