Urease activity does not reflect the degree of colonization by Helicobacter pylori in children

BACKGROUND: Urea breath test is an accurate method for the diagnosis of Helicobacter pylori infection in children. This test could estimate the bacterial load by measuring the urease activity in gastric mucosa. The aim of the study was to correlate the result of 13C-urea breath test (13C-UBT) and histological estimative for bacterial colonization and severity of inflammatory infiltrate. METHODS: Forty-four patients (mean age 8.54 +/- 3.9 years) with dyspeptic symptoms were evaluated. Patients were evaluated through endoscopy and 13C-UBT. Helicobacter pylori infection was defined by histology, rapid urease test and 13C-UBT. Breath test results were expressed by delta over baseline (DOB) and urea hydrolysis rate (UHR). Test results were treated logarithmically for statistical analysis. RESULTS: There was a significant inverse correlation between age and Log DOB (-0.501, P= 0.0005), but there was no relationship between Log UHR and age (-0.148, P= 0.336). The study did not find correlation between the breath test result and histological grades for mononuclear infiltrate, neutrophilic infiltrate and bacterial density. CONCLUSION: The 13C-UBT does not estimate the severity of histological findings in children with Helicobacter pylori infection. The results of the breath test should be interpreted in a qualitative way.     

13 C-urea breath test with infrared spectroscopy for diagnosing helicobacter pylori infection in children and adolescents

BACKGROUND AND OBJECTIVE: Studies support the accuracy of 13C-urea breath test for diagnosing and confirming cure of Helicobacter pylori infection in children. Three methods are used to assess 13CO2 increment in expired air: mass spectrometry, infrared spectroscopy, and laser-assisted ratio analysis. In this study, the 13C-urea breath test performed with infrared spectroscopy in children and adolescents was evaluated. METHODS: Seventy-five patients (6 months to 18 years old) were included. The gold standard for diagnosis was a positive culture or positive histology and a positive rapid urease test. Tests were performed with 50 mg of 13C-urea diluted in 100 mL orange juice in subjects weighing up to 30 kg, or with 75 mg of 13C-urea diluted in 200 mL commercial orange juice for subjects weighing more than 30 kg. Breath samples were collected just before and at 30 minutes after tracer ingestion. The 13C-urea breath test was considered positive when delta over baseline (DOB) was greater than 4.0%. RESULTS: Tests were positive for H. pylori in 31 of 75 patients. Sensitivity was 96.8%, specificity was 93.2%, positive predictive value was 90.9%, negative predictive value was 97.6%, and accuracy was 94.7%. CONCLUSIONS: 13C-urea breath test performed with infrared spectroscopy is a reliable, accurate, and noninvasive diagnostic tool for detecting H. pylori infection.     

Influence of age on 13C-urea breath test results in children

BACKGROUND: The 13C-urea breath test for diagnosis of Helicobacter pylori infection has not been validated in infants and young children. The influence of age on the test results was studied by conventional validation against invasive methods and by mathematical estimation in a large pediatric population. METHODS: The breath test was performed in 1499 children aged 2 months to 18 years. After a fasting period of 4 hours or more, 75 mg 13C-urea was ingested with cold apple juice, breath samples were taken at baseline and at 15 and 30 minutes. The distribution of the natural logarithms of the delta-over baseline (DOB) values were calculated, and the optimal cutoff values between positive and negative test results and gray zones with a risk of misclassification more than 10% were determined for both time points. In a subgroup of 149 children results of the breath test were compared with concordant results of histology and rapid urease test; 53 of them were less than 6 years of age. RESULTS: Logarithmic results of 1499 breath tests revealed two normally distributed subgroups with minimal overlap. The calculated optimal cutoff values were 4.7/1000 at 15 minutes and 5.0/1000 at 30 minutes. At 30 minutes, only 2.6% of all results were in the calculated gray zone (2.6-6.5/1000). Age was negatively correlated to DOB values of both negative (r = -0.223) and positive results (r = -0.291; P < 0.001). Breath test-negative and -positive children 6 or less years of age had significantly higher mean DOB values (P < 0.02) and a larger proportion of results within the gray zone than older children. Compared with biopsy-based results, the least discrepancies occurred at a cutoff of 5.0/1000: 0 of 61 infected (sensitivity 100%) and 6 of 88 noninfected children. Because five of the false-positive results were obtained in children less than 6 years of age, specificity and positive predictive values were lower in this age group than in older patients (88.1% vs. 97.8% and 68.8% vs. 98.0%, respectively). CONCLUSIONS: Under the applied conditions, the 13C-urea breath test shows an excellent separation between positive and negative results. Because of some overlap and a strong age effect, definition of a gray zone appears more meaningful than a threshold value. Because infants and young children have a high risk for false-positive breath test results, the values for cutoff and gray zones may have to be adapted. Further validation studies against invasive methods are warranted in this age group.     

Breath test using a single 50-mg dose of 13C-urea to detect Helicobacter pylori infection in children

BACKGROUND: The 13C-urea breath test is an accurate, noninvasive method for the diagnosis of in adults. A dose of 75 to 100 mg of urea is generally used, especially in adults, but the optimal dose in children is still unknown. Our aim was to determine whether urea breath test performed with a single 50-mg dose of 13C-urea was sufficient and accurate for diagnosing infection in children. METHODS: Consecutive children 4 to 14 years of age undergoing upper intestinal endoscopy to evaluate symptoms of recurrent abdominal pain were prospectively included. Exclusion criteria included use of antibiotics or proton pump inhibitors during the last month, gastric surgery, and previous eradication therapy. Reference criteria for diagnosis of infection were based on histology, culture, and serology. Urea breath test (TAU-KIT; Isomed, S.L., Madrid, Spain) was performed as follows: citric acid (Citral pylori) dissolved in 100 mL of water was initially given. Ten minutes later, a baseline exhaled breath sample was collected, and thereafter 50 mg of 13C-urea dissolved in 50 mL of water was given. A second breath sample was obtained 30 minutes later. Breath samples were analyzed by isotope ratio mass spectrometry. The endoscopist, the pathologist, the microbiologist, and the person responsible for reading the serology and the urea breath test were all unaware of status by the other diagnostic methods. RESULTS: One hundred children were included (40% males; mean age, 9.2 +/- 2 years; mean weight, 33.9 +/- 12 kg). Based on the reference criteria, 45% were infected, 37% were not infected, and 18% were indeterminate. Sensitivity, specificity, positive predictive value, and negative predictive value were, respectively, 91% (95% confidence interval [CI], 79%-96%), 97% (95% CI, 86%-99%), 98% (95% CI, 87%-91%), and 90% (95% CI, 76%-96%). Positive and negative likelihood ratios were of 33 and 0.09. Any cutoff point between 2 and 14 delta units had the same high diagnostic accuracy. The area under the receiver operating characteristic curve was 0.94. No adverse effects were reported. CONCLUSION: Urea breath test using 50 mg of urea is sufficient and accurate for the diagnosis of infection in children. Use of a small test dose significantly lowers the cost of the test.     

Interpreting the 13C-urea breath test among a large population of young children from a developing country.

The 13C-urea breath test is a noninvasive tool for the diagnosis of gastric Helicobacter pylori infection. However, it has not been validated in young children from the developing world, where infection is very common. 13C urea breath tests were performed on 1532 occasions on 247 Gambian infants and children aged from 3 to 48 mo. The means and variances of the separate sub-populations of 13C enrichment results contained within the overall dataset were estimated by a Genstat procedure using the EM algorithm, thereby identifying a cut-off value to discriminate positive from negative results. To illustrate the appropriateness of this calculated cut-off value, 13C urea breath tests were performed upon a small group of 14 patients aged 6 to 28 mo undergoing diagnostic upper endoscopy. Fixed gastric antral biopsies were examined to identify H. pylori. Two subpopulations were identified within the large dataset. A cut-off value of 5.47 delta per thousand relative to Pee Dee Belemnite limestone above baseline at 30 min identified 95% of the normally distributed negative sub-population and 99.4% of the log normal distributed positive sub-population. Comparison with endoscopic data confirmed that this cut-off value was appropriate for this population, as 7/7 children without H. pylori on their gastric biopsies had negative urea breath tests, and 6/7 children with gastric H. pylori colonization had positive urea breath tests. These findings confirm the value of the urea breath test as a diagnostic tool in young children from developing countries. They also offer a way to calculate the most appropriate cut-off value for use in different populations and the likelihood that it will correctly assign any value into the appropriate sub-population, without the need for endoscopy.     

Accuracy of serology and 13C-urea breath test for detection of Helicobacter pylori in children

BACKGROUND: Indirect noninvasive methods, such as the 13C-urea breath test and serology, can be useful for the detection of Helicobacter pylori infection in children. We analyzed retrospectively the diagnostic accuracy of these two methods. PATIENTS AND METHODS: Between September, 1989, and October, 1996, H. pylori status was determined in 139 children by means of culture and histologic study of gastric biopsies. We performed 146 13C-urea breath tests and serologic assays (Cobas core; Roche). RESULTS: H. pylori infection was detected in 91 of 139 (65%) children. The 13C-urea breath test was discordant with H. pylori status in 4 of 146 tests; serology was discordant in 24 and indeterminate in 7 of 146. The 13C-urea breath test was more sensitive than serology (98% vs. 79%, P < 0.01) but comparable in specificity (96% vs. 92%). The serology yielded false negative results more often in children younger than 5 years of age (P < 0.05). CONCLUSIONS: The 13C-urea breath test is more reliable than serology for the detection of active H. pylori infection in children. Below 10 years of age serology is insufficiently sensitive for clinical purposes, whereas the 13C-urea breath test remains a reliable test.     

Helicobacter pylori infection and cytotoxic antigen associated gene "A" status in short children.

BACKGROUND: Helicobacter pylori is now an accepted gastroduodenal pathogen and is being investigated for possible implications in nongastroenterological conditions such as growth impairment. Subjects infected by cytotoxic Cag-A positive strains seem more likely to develop serious gastroduodenal diseases but the possible role of Cag-A positive strains in non gastroenterological diseases has not been fully investigated. OBJECTIVE: 1) To evaluate the prevalence of Helicobacter pylori infection and Cag-A positivity in short children compared to auxologically normal children. All the subjects were without gastro-intestinal symptoms and were not obese or significantly underweight. 2) To verify the reliability of the ELISA assay for H. pylori. SUBJECTS: H. pylori infection was assessed in 338 children, 182 auxologically normal and 156 short children, with and without deficiency in growth hormone, by the determination of specific IgG antibody. In 79 subjects (all seropositive and a random sample of seronegative children), 13C-urea breath test and cytotoxic Cag-A positive strains were examined. RESULTS: The overall seroprevalence of H. pylori infection by IgG antibody was 18/156 (11.5%) and 13/182 (7.1%) in short and auxologically normal children respectively. The 13C-urea breath test was positive in 29 children: 17 (10.9%) short and 12 (6.6%) auxologically normal. Western blotting documented infection by cytotoxic Cag-A positive strains in 12/17 (70.6%) and 8/12 (66.6%) of short and auxologically normal children respectively. None of the differences between the two groups were significant. CONCLUSIONS: 1) We found a similar prevalence of H. pylori infection and Cag-A positivity in two large pediatric populations of short or auxologically normal children. Therefore: 1) Our data did not confirm a role of H. pylori infection in short stature in children. 2) We found a high reliability of ELISA assay for the detection of IgG antibodies compared to breath test.     

Prevalence of Helicobacter pylori infection detected by serology and 13C-urea breath test in HIV-1 perinatally infected children

BACKGROUND: Conflicting results have been reported in adults with human immunodeficiency virus (HIV-1) who were investigated for Helicobacter pylori infection. Most studies indicate a lower prevalence than is found in the general population. The purposes of this study were to evaluate H. pylori prevalence by noninvasive methods in a population of children perinatally infected with HIV-1 and to correlate H. pylori prevalence with HIV-1-related clinical and immunologic status. METHODS: H. pylori infection was studied in 45 children perinatally infected with HIV-1 by performing serologic testing of anti-H. pylori immunoglobulin G antibodies and the 13C-urea breath test. RESULTS: Eight children with HIV-1 (17.7%) were positive by serology, and nine (20%) were positive by 13C-urea breath test. No significant differences related to age, previous antibiotic treatment, immunoglobulin administration, antiretroviral treatment, abdominal pain, CD4+ cell count, number of HIV-1 RNA copies, and frequency of severe immunodepression were noted between children with positive 13C-urea breath test results and those with negative results. Children with positive results were significantly more likely to have severe clinical manifestations. CONCLUSIONS: The results show, by both serology and 13C-urea breath test, a prevalence of H. pylori infection comparable with the prevalence in the normal population of the same age. H. pylori prevalence has probably been underestimated in patients with HIV. Results of serologic and histologic analyses for H. pylori require cautious interpretation, especially in severely immunodeficient patients.     

Helicobacter pylori colonization in early life

Helicobacter pylori infection is a major cause of upper gastrointestinal disease throughout the world. Colonization begins in childhood, although little is known about its age of onset, rate, or mode of colonization. Our aim was to identify the age of acquisition of H. pylori colonization in Gambian children. A cohort of 248 Gambian children aged 3 to 45 months was studied at intervals of 3 months for 2 years, using the 13C-urea breath test, specific IgM and specific IgG serology. The prevalence of positive breath tests rose from 19% at 3 months of age to 84% by age 30 months. Elevated specific IgG and IgM antibody levels were associated with positive breath tests, although there was discrepancy between breath test results and serology, particularly IgG serology, during the 1st year of life. Neither IgG nor IgM serology could be validated as reliable diagnostic tools for infant H. pylori colonization compared with the 13C-urea breath test. Reversion to negative breath test, in association with declining specific antibody levels, occurred in 48/248 (20%) of children. On the assumption that the 13C-urea breath test is a reliable index of H. pylori colonization, we conclude that the infection is extremely common from an early age in Gambian children. Transient colonization may occur. Previous studies relying on serodiagnosis may have significantly underestimated the true early prevalence of colonization in the developing world, where the target age for intervention studies is probably early infancy.     

Contribution of the 13C-urea breath test to the detection of Helicobacter pylori gastritis in children.

Serology, 13C-urea breath test, histology, Campylobacter-like organism testing, and culture were performed in 95 consecutive children to evaluate the contribution of these tests to the detection of Helicobacter pylori infection. In analyses considering any combination of three positive tests as "gold standard" for diagnosing H pylori infection, 26 children were Helicobacter positive (27%), which is only one patient more than the number of children with only a positive culture. The accuracy of culture was excellent when "any combination of three positive tests" was used as the gold standard (sensitivity 96%, specificity 100%, positive predictive value 100% [false positivity 0%], negative predictive value 99% [false-negative results 1%]). The results of invasive and noninvasive tests were comparable. When culture was considered as "gold standard," the sensitivity of serology and 13C-urea breath test was 96%; the specificity was 96% and 93%, respectively; the positive predictive value was 89% and 83% (false-positive results in 11% and 17%); and the negative predictive value for both was 99% (false-negative results in 1%). It is concluded that culture can be used as gold standard, but that non-invasive tests such as serology and/or 13C-urea breath test can be used to diagnose H pylori infection in children, since each has at least 95% sensitivity and 92% specificity.     

幽门螺杆菌粪便抗原检测在幽门螺杆菌感染的应用

目的　评估幽门螺杆菌粪便抗原 (HpSA)试验在幽门螺杆菌 (Hp)感染治疗前后的准确性。方法　收集 62例 4～ 1 7岁因上消化道症状就诊而接受1 3C 尿素呼气试验 (1 3C UBT)、胃镜检查和 31例根除Hp后停药至少 4周 ,接受1 3C 尿素呼气试验 2d内患儿粪便标本 ,应用酶免疫反应原理进行HpSA试验 ;以1 3C UBT检测和胃镜活检作为诊断标准。结果　以光密度值 (A)≥0 .1 2 1为阳性 ,HpSA检测治疗前诊断Hp感染敏感性为 92 .30 %、特异性 91 .30 %、阳性预测值为 92 .30 %、阴性预测值 87.50 %、准确性 91 .94% ;治疗后诊断Hp感染敏感性为 83 .33 %、特异性 88.0 0 %、阳性预测值为 62 .50 %、阴性预测值 95 .65 %、准确性 87.1 0 %。结论　HpSA检查对治疗前诊断儿童Hp感染准确率较高 ;对治疗后的诊断敏感性和特异性较治疗前低。     

Helicobacter pylori infection in children of Texas

BACKGROUND: Acquisition of the Helicobacter pylori infection usually occurs in childhood. The prevalence of infection differs among ethnic groups and in adults is inversely related to the socioeconomic status of the individual's family during childhood. This study investigates the seroprevalence of H. pylori infection in children of different ethnic groups in relation to socioeconomic class and investigates the prevalence of acute H. pylori infection among children who have had recent onset of abdominal pain. METHODS: Serum samples were collected from 797 children, aged 6 months to 18 years, of various socioeconomic and ethnic backgrounds, at a large urban children's hospital. H. pylori status was determined by an anti-H. pylori immunoglobulin (Ig)G enzyme-linked immunosorbent assay (ELISA) validated for pediatric use. To determine the prevalence of acute H. pylori infection, children brought to the emergency center with abdominal symptoms without diarrhea and overt signs of acute abdomen were evaluated with both serology and the 13C-urea breath test. Acute H. pylori was defined as a positive 13C-urea breath test result and negative IgG serology for H. pylori. RESULTS: The overall seroprevalence of H. pylori was 12.2% and increased with age (e.g., 8.3% at 6-11.9 months and 17.9% at 13 years). The prevalence was inversely related to socioeconomic status (6.6%, moderate to high vs. 15%, low socioeconomic status). The difference in seroprevalence among blacks (16.8%), Hispanics (13.3%), and whites (8.3%; P < 0.01) could be accounted for by differences in socioeconomic status. Eighteen percent of children who were evaluated at the emergency center for recent-onset abdominal pain had acute H. pylori infections. CONCLUSIONS: Socioeconomic status, not ethnic group, is the more important risk factor for acquisition of H. pylori infection during childhood. Acute H. pylori infection was a relatively common cause of recent-onset, nonsurgical abdominal pain.     

Accurate diagnosis of Helicobacter pylori infection by stool antigen test and 6 other currently available tests in children

Invasive and noninvasive tests have been developed for the diagnosis of Helicobacter pylori infection. Because H pylori infection is acquired in childhood and adolescence, accurate diagnosis of the infection in the pediatric population is important. We conducted a study to compare invasive tests: culture, biopsy urease test, histology, and polymerase chain reaction on gastric biopsy specimens, with noninvasive tests: serology, (13)C-urea breath test, and a new diagnostic modality, stool antigen test to diagnose H pylori infection. A total of 53 children with symptoms were enrolled in this study, and all had completed the 7 diagnostic tests for H pylori. All the diagnostic tests except serology were excellent methods of diagnosing H pylori infection in children; the diagnostic accuracy was as follows: stool antigen test 96.2%, biopsy urease test 96.2%, histology 98.1%, polymerase chain reaction 94.3%, culture 98.1%, (13)C-urea breath test 100%, and serology 84.9%. The stool antigen test, being highly sensitive and specific, will be potentially very helpful in diagnosing H pylori infection in children.     

Limitations to carbon 13-labeled urea breath testing for Helicobacter pylori in infants.

We determined the validity of the carbon 13-labeled urea breath test in young children. We found that although the 13C-labeled urea breath test had a specificity greater than 90%, borderline or false positive results occurred more frequently in children younger than 2 years compared with older children. False positive results may be caused by oral-urease-producing organisms because direct intragastric administration of 13C urea reduced the excess delta 13CO2. Care is urged in interpreting one positive 13C-labeled urea breath test in children younger than 2 years.     

13C mixed triglyceride breath test: a noninvasive method to assess lipase activity in children.

BACKGROUND: Results from the 13C mixed triglyceride (MTG) breath test correlate with duodenal lipase activity in adults. This noninvasive test is a potential screening and diagnostic tool for children with fat malabsorption. The aim of this study was to adapt the methodology of the MTG breath test to study test meals and sampling methods and to define normal values for healthy children of all age groups; premature and full-term infants have similar pancreatic lipase deficiencies. METHODS: After parental consent was obtained, 12 premature infants (< 37 weeks gestation and with body weights > 2 kg), 12 full-term infants (1-6 months old), 20 children (3-10 years old), and 20 teenagers (11-17 years old) were tested. All children were thriving well, had no gastrointestinal or respiratory problems, and had not received any medication that contained natural 13C. For the premature and full-term infants, a formula was prepared that had a low and stable natural 13C content mixed with 100 mg 13C-labeled MTG (1,3-distearyl, 2-[13C-carboxyl] octanoyl glycerol) and 1 g polyethylene-glycol 3350. The best accepted test meal for children over 3 years old was a slice of white bread with 5 g butter and 15 g chocolate paste, mixed with 250 mg 13C-labeled MTG, and a glass of 100 mL whole-fat milk. Children over 3 years old were able to blow through a straw in a vacutainer for collecting the breath samples. In children under 3 years old, expired air was collected by aspirating breath via a nasal prong. Carbon dioxide production was calculated according to weight, age, and sex. RESULTS: For healthy pediatric control participants, the mean values for cumulative excretion of 13CO2 as a percentage of the administered dose after 6 hours were 23.9 +/- 5.2% in premature infants, 31.9 +/- 7.7% in full-term infants, 32.5 +/- 5.3% in children, and 28.0 +/- 5.4% in teenagers. The mean value for healthy adults is 35.6% with a lower reference limit of 22.8%. CONCLUSIONS: Age-specific test meals and breath-sampling techniques for the MTG breath test were defined. The mean values for different age groups may serve as guidelines for normal values in the pediatric population. The cumulative values for expired 13CO2 were above the lower limit for adults, which suggests that preduodenal lipases compensates for pancreatic lipase deficiency in premature and full-term infants.     

Helicobacter pylori status and symptom assessment two years after eradication in pediatric patients from a high prevalence area

OBJECTIVES: To establish the rate of Helicobacter pylori reinfection in children from an H. pylori high prevalence area, possible clinical features predictive of reinfection and the usefulness of re-treatment. METHODS: 65 consecutive children attending the authors' department between 1998 and 2000 who had proven successful H. pylori eradication were enrolled; 52 took part. Patients and family members were invited to undergo C-urea breath testing and to complete a simple questionnaire regarding symptoms and socioeconomic status. Patients with H. pylori reinfection were offered treatment; eradication was assessed by C-urea breath test 8 weeks after completion of treatment. RESULTS: Of 52 children, 15 (28.8%) were H. pylori positive. Variables predictive of reinfection were age at primary infection and presence of an infected sibling. Although reinfected children were more frequently symptomatic than non-reinfected patients, no specific symptom was associated with reinfection. Of the nine re-treated patients who returned 8 weeks after completing therapy, the bacterium was eradicated in five (56%). CONCLUSIONS: The 12.8% per year reinfection rate in childhood at 2 years that we observed should prompt a re-evaluation of H. pylori status even after a successful eradication. Living in an H. pylori high prevalence area increases the annual risk of reinfection by approximately fourfold over the annual risk in H. pylori low prevalence areas.     

序贯疗法和标准三联疗法根除儿童幽门螺杆菌的疗效观察

目的评估序贯疗法在儿童幽门螺杆菌感染根治治疗中的疗效及可行性。方法将有上消化道症状,经13C-尿素呼气试验(13C-UBT)检测H.pylori为阳性的患儿100例随机分为3组:序贯治疗组、PAC组和PAM组。序贯治疗组:前5 d二联疗法即奥美拉唑+阿莫西林,后5 d三联疗法即奥美拉唑+克拉霉素+甲硝唑;PAC组予以奥美拉唑+阿莫西林+克拉霉素,共10 d;PAM组予以奥美拉唑+阿莫西林+甲硝唑,共10 d。均为每日2次,早晚口服。所有患儿停药至少4周后复查13C-UBT,判断H.pylori根除率。结果三组患儿H.pylori根除率的符合方案数据分析(PP)分别为:序贯治疗组91.18%,PAC组68.97%,PAM组76.67%;序贯治疗组和PAC组比较,差异有统计学意义(χ2=5.01,P<0.05);序贯治疗组和PAM组比较,PAC组和PAM组比较,差异均无统计学意义(χ2=2.55、0.44,P均>0.05)。结论 10日序贯疗法根除H.pylori疗效明显优于10日标准三联疗法,10日序贯疗法可能为一有效的根除儿童H.pylori感染的新方案。     

Impact of Helicobacter pylori infection on growth of children: a prospective cohort study

OBJECTIVE: The aim of this study was to prospectively follow a cohort of children without Helicobacter pylori infection and to compare growth velocity in the children who become infected during follow-up with that of children who remained infection-free. METHODS: Three hundred forty-seven children in general good health, aged 12 to 60 months, who tested negative for H. pylori by the 13C-urea breath test, from three daycare centers in a lower-middle class borough of Cali, Colombia, were monitored for 2.5 years. Anthropometric measurements were performed every 2 months and breath tests every 4 months. Linear mixed models were used to analyze growth velocity in relation to onset of H. pylori infection. RESULTS: One hundred five (30.3%) children who were uninfected at the start of the study became infected during follow-up. Growth velocity in infected children was reduced by 0.042 +/- 0.014 cm/mo (P = 0.003) (approximately 0.5 cm/yr) after adjusting for age. The rate of deceleration in growth velocity was relatively constant over time. CONCLUSIONS: Among these lower-middle class children aged 12 to 60 months from a population with high prevalence of H. pylori infection, a new and sustained infection was followed by significant growth retardation.     

Comparison of an enzyme immunoassay for the detection of Helicobacter pylori antigens in the faeces with the urea breath test.

BACKGROUND: Current diagnostic tests for Helicobacter pylori are invasive (endoscopy) or indirect (urea breath test, serology). AIMS: To evaluate a new enzyme immunoassay (EIA) which detects H pylori antigens in faeces, by comparing its sensitivity and specificity in children with the (13)C urea breath test (UBT). METHODS: A total of 119 children underwent a UBT and provided a faecal sample for antigen testing within seven days. After an overnight fast each child provided a pretest breath sample, and samples at 30 and 40 minutes after ingestion of 100 mg (13)C labelled urea. (13)C enrichment of breath was measured by isotope ratio mass spectrometry. Faeces were stored at -70 degrees C until antigen testing, using the EIA. Samples were read spectrophotometrically at 450 nm and results were interpreted using recommended cut offs of optical density <0.14 as negative, >/=0.16 as positive, with >/=0.14 and <0. 16 representing equivocal results. Sensitivity and specificity were calculated using the manufacturer's cut off compared with UBT. RESULTS: Sensitivity and specificity were 88% and 82%, respectively. Negative and positive predictive values were 97% and 58%. CONCLUSIONS: The EIA is an alternative, non-invasive, and easy to use method for the detection of H pylori in children. Its high negative predictive value suggests a role in screening out uninfected children.     

Helicobacter pylori infection and growth delay in older children

It is thought that Helicobacter pylori infection may influence growth rate in children. The aim of this study was to evaluate the prevalence of H pylori infection in healthy Italian children, and to look for differences in height between infected and non-infected subjects. Two hundred and sixteen children, aged 3 to 14 years, were tested for H pylori infection by 13C-urea breath test. Centile values for height were calculated. Composite indices for socioeconomic class and household crowding were also determined. Forty nine of 216 children (22.7%) were H pylori positive. The prevalence of infection increased with age. Eight of 49 H pylori positive children (16.3%) were below the 25th centile for height, compared with 13 of 167 H pylori negative children (7.8%). This difference became significant in children aged 8.5 to 14 years; in this group (n = 127), eight of 31 infected children (25.8%) were below the 25th centile for height, compared with eight of 96 non-infected children (8.3%). A significant correlation was found between socioeconomic conditions, household crowding, and H pylori status. By using stepwise logistic regression, only the centile value for height was significantly related to H pylori status in older children. Thus H pylori infection was associated with growth delay in older children, poor socioeconomic conditions, and household overcrowding. This finding is consistent with the hypothesis that H pylori infection is one of the environmental factors capable of affecting growth.