Natural history of Helicobacter pylori infection in Mexican schoolchildren: incidence and spontaneous clearance.

OBJECTIVES: The aim of the present study was to estimate the incidence and spontaneous clearance rate of Helicobacter pylori infection and the effect of some variables on these outcomes in schoolchildren. METHODS: From May 2005 to December 2010, 718 schoolchildren enrolled in 3 public boarding schools in Mexico City participated in the follow-up. At the beginning of the study and every 6 months thereafter, breath samples were taken to detect H pylori infection; blood samples and anthropometric measurements were taken to evaluate nutritional status. Data on sociodemographic characteristics were collected. RESULTS: The prevalence of H pylori infection was 38%. The incidence rate was 6.36%/year. Schoolchildren with anemia or iron deficiency at the beginning of the study (who received iron supplements) showed a higher infection acquisition rate than those with normal iron nutritional status, hazard ratio (HR) 12.52 (95% confidence interval [CI] 4.01%-39.12%), P < 0.001 and HR 2.05 (95% CI 1.09%-3.87%), P = 0.027, respectively. The spontaneous clearance rate of the infection was 4.74%/year. The spontaneous clearance rate was higher in children who had iron deficiency (who received iron supplements), HR 5.02 (95% CI 1.33%-18.99%), P = 0.017, compared with those with normal nutritional iron status. It was lower in schoolchildren with ≥ 2 siblings compared with schoolchildren with 1 or no siblings, HR 0.23 (95% CI 0.08%-0.63%), P = 0.004. CONCLUSIONS: H pylori infection status is dynamic in schoolchildren. Variables related to health status and infection transmission, such as iron status and number of siblings, are important for the incidence and spontaneous clearance of H pylori infection.

Maté consumption and risk of cancer: a multi-site case-control study in Uruguay.

In the time period 1990-2004 we conducted a multisite case-control study in order to examine the relationship of mate consumption and risk of 13 cancer sites in Montevideo, Uruguay. The study included 13,201 participants (8,875 cases and 4,326 controls) drawn from the four major public hospitals in the city of Montevideo. Newly diagnosed and microscopically confirmed cases of cancers of the mouth, pharynx, esophagus, stomach, colon, rectum, larynx, lung, female breast, cervix uteri, prostate, bladder and kidney were included in the study. Controls were drawn from the same hospitals and in the same time period and were afflicted by non-neoplastic conditions not related with tobacco smoking or alcohol drinking and without recent changes in their diets. Odds ratios for mate consumption was directly associated with cancers of the upper aerodigestive tract (UADT), esophagus, stomach, larynx, lung, cervix uteri, prostate, bladder, and kidney. In conclusion these results suggest that chemicals, like benzo[a]pyrene, could be responsible of the carcinogenic effect of mate in the above mentioned cancer sites.

Effect of eradication of Helicobacter pylori and iron supplementation on the iron status of children with iron deficiency.

BACKGROUND AND AIMS: We undertook this study to evaluate the effect of Helicobacter pylori eradication and iron supplementation on the iron nutritional status in children with iron deficiency. METHODS: Seven hundred and one children from four public schools in Mexico City were screened to evaluate their iron status. Of them, 72 children with iron deficiency or with anemia were included in this study and were tested for H. pylori infection. Those infected were given eradication treatment and were randomly assigned to daily supplementation for 3 months with ferrous sulfate or placebo. Noninfected children received ferrous sulfate. At the end of the interventions, blood samples were drawn to evaluate their effects on the nutritional status of iron. RESULTS: Thirty eight children with iron deficiency or anemia were infected by H. pylori at baseline. The eradication rate was 86.8%. Children in whom H. pylori eradication was achieved showed an increase of 0.37g/dL (95% CI -0.02, 0.75) on the hemoglobin mean concentration compared to the noninfected children. Children who achieved H. pylori eradication and received ferrous sulfate supplementation showed an increase of 0.47g/dL (95% CI 0.01-0.93) on the hemoglobin mean concentration compared to the noninfected children who received iron supplementation. Noninfected children supplemented with ferrous sulfate showed an increase in ferritin concentration of 11.26 ng/mL (95% CI 1.86-20.65) compared to those who were given the placebo. CONCLUSIONS: Our results suggest that the eradication of H. pylori plus iron supplementation increases the pool of functional iron. Iron supplementation increases the storage of iron in school-age children with iron deficiency.

Plasma selenium measurements in subjects from areas with contrasting gastric cancer risks in Colombia.

BACKGROUND: An inverse association between selenium status and incidence of different neoplasias including gastric cancer has been reported. This pilot study aimed to determine and compare selenium status in two Colombian populations with different gastric cancer risks: a high-risk area in the volcanic region of the Andes Mountains and a low-risk area on the Pacific coast. METHODS: Eighty nine adult males were recruited in the outpatient clinics of two public hospitals (44 and 45 from high- and low-risk areas, respectively) and provided a blood sample. Seventy one (79.8%) participants underwent upper gastrointestinal endoscopy. Plasma selenium was assayed using a fluorometric method, selenoprotein-P by ELISA, and glutathione peroxidase activity by a spectrophometric method. Histological diagnosis and Helicobacter pylori infection were evaluated in gastric biopsy samples. Unpaired samples t-test and linear regression analyses were used for statistical analyses. RESULTS: Although none of the subjects in either of the two geographic areas was selenium deficient, the level of plasma selenium was significantly lower in men from the high-risk area compared with those from the low-risk area. Levels of selenoprotein-P and glutathione peroxidase activity were similar between groups after adjustment for confounders. Selenium measurements were not associated with histopathological diagnosis. CONCLUSIONS: The high incidence of gastric cancer in the Andean region of Colombia is unlikely to be explained by selenium deficiency. We cannot exclude, however, that suboptimal selenium levels may exist in the gastric mucosa of subjects in the high-risk area. Therefore, the benefit of selenium supplementation in gastric cancer prevention cannot be dismissed.

Fuentes de variabilidad en el diagnóstico de gastritis atrófica multifocal asociada con la infección por Helicobacter pylori / Source of variation in the diagnosis of Helicobacter pylori-associated multifocal atrophic gastritis

Introducción: El mapeo de las diferentes regiones del estómago y el número de fragmentos de mucosa gßstrica disponibles para evaluación histopatológica son fuentes importantes de variación en el momento de clasificar y hacer la gradación de la gastritis crónica. Objetivos: Estimar la sensibilidad del número de fragmentos de mucosa gßstrica necesarios para establecer los diagnósticos de gastritis atrófica con metaplasia intestinal (MI), displasia y estado de infección por Helicobacter pylori. Ademßs evaluar la variabilidad intra-observador en la clasificación de estas lesiones precursoras del cancer gastrico. Materiales y métodos: En una cohorte de 6 a±os de seguimiento se evaluaron 1,958 procedimientos de endoscopia realizados por dos gastroenterólogos. En cada procedimiento y de cada participante se obtuvieron 5 biopsias de mucosa gßstrica que representaban antro, incisura angularis y cuerpo. Un único patólogo hizo la interpretación histológica de las 5 biopsias y proporcionó un diagnóstico definitivo global que se utilizó como patrón de referencia. Cada fragmento de mucosa gßstrica examinado condujo a un diagnóstico individual para cada biopsia que se comparó con el patrón de referencia. La variabilidad intra-observador se evaluó en 127 personas que corresponden a una muestra aleatoria de 20% del total de endoscopias hechas a los 72 meses de seguimiento. Resultados: La sensibilidad del diagnóstico de MI y displasia gßstrica aumentó de manera significativa con el número de fragmentos de mucosa gßstrica evaluados El sitio anatómico de mayor sensibilidad para el diagnóstico de MI y displasia fue la incisura angularis. Para descubrir H. pylori se logró alta sensibilidad con el estudio de un solo fragmento de mucosa gastrica (95.9%) y fue independiente del sitio de obtención de la biopsia. El acuerdo intra-observador para el diagnóstico de gastritis crónica fue 86.1% con valor kappa de 0.79 IC 95% (0.76-0.85).

Introduction: Multiple sampling from different sites of the stomach as well as the number of fragments of gastric mucosa available for histopathologic evaluation are important sources of variation when classifying and grading chronic gastritis. Objective: To estimate the sensitivity of the number of fragments of gastric mucosa necessary to establish the diagnosis of atrophic gastritis with intestinal metaplasia, gastric dysplasia and H. pylori infection. In addition, this study will attempt to assess the intra-observer variability in the classification of these premalignant gastric lesions. Methods: This is a 6 year-cohort study, wherein 1958 gastric endoscopic procedures performed by two gastroenterologists were reviewed. Five gastric biopsy samples were obtained from the antrum, body and lesser curvature during each procedure. One pathologist was in charge of reviewing the five histopathology samples for each subject and providing a definitive diagnosis which was used as the gold standard. Each gastric mucosa sample reviewed led to an individual diagnosis for that sample which was compared with the gold standard. Intra-observer variability was assessed in 127 individuals who correspond to a random sample of 20% of the total endoscopic procedures performed during the 72 month-follow-up. Results: The sensitivity of the diagnosis of intestinal metaplasia (IM) and gastric dysplasia increased proportionally with the number of gastric mucosa samples reviewed. The lesser curvature of the stomach had the highest sensitivity for the diagnosis of IM and dysplasia, among all the stomach regions studied. Just one sample of gastric mucosa attained a sensitivity of 95.9% for the detection of H. pylori infection. The intra-observer agreement for the diagnosis of multifocal atrophic gastritis was 86.1% and the kappa value was 0.79 (95% CI 0.76-0.85). Alcohol-fixed biopsy specimens were inadequate to diagnose H. pylori infection and to assess dysplasia.

Non-alcoholic beverages and risk of bladder cancer in Uruguay.

BACKGROUND: Bladder cancer is the fourth most frequent malignancy among Uruguayan men. A previous study from Uruguay suggested a high risk of bladder cancer associated with maté drinking. We conducted an additional case-control study in order to further explore the role of non-alcoholic beverages in bladder carcinogenesis. METHODS: In the time period 1996-2000, 255 incident cases with transitional cell carcinoma of the bladder and 501 patients treated in the same hospitals and in the same time period were frequency matched on age, sex, and residence. Both cases and controls were face-to-face interviewed on occupation, tobacco smoking, alcohol drinking and intake of maté, coffee, tea, and soft drinks. Statistical analysis was carried out by unconditional multiple logistic regression. RESULTS: Ever maté drinking was positively associated with bladder cancer (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.2-3.9) and the risk increased for increasing duration and amount of maté drinking. Both coffee and tea were strongly associated with bladder cancer risk (OR for coffee drinking 1.6, 95% CI 1.2-2.3; OR for tea drinking 2.3, 95% CI 1.5-3.4). These results were confirmed in a separate analysis of never-smokers. CONCLUSION: Our results suggest that drinking of maté, coffee and tea may be risk factors for bladder carcinoma in Uruguay.

New strategies for the prevention of gastric cancer: Helicobacter pylori and genetic susceptibility.

Recently acquired knowledge points to the potential of markedly improved strategies for the prevention of gastric cancer. The International Agency for Cancer Research has reached the conclusion that infection with Helicobacter pylori (H. pylori) is carcinogenic to humans (Group I). The bacterium displays marked genetic heterogeneity. Virulence related genes, especially cag A and vac A s1 m1 are associated with an increased cancer risk. Genetic susceptibility, especially polymorphisms of the cytokine genes may increase cancer risk. Highly susceptible individuals infected with high virulence bacterial genotypes have a markedly increased gastric cancer risk. They should be targeted for endoscopic monitoring to detect advanced precancerous lesions. The state of the art is briefly reviewed and the needed research identified.

Increased reflux symptoms after calcium carbonate supplementation and successful anti-Helicobacter pylori treatment.

We used data from a randomized placebo-controlled clinical trial to examine the relationship between Helicobacter pylori and reflux symptoms in nonulcer dyspepsia patients randomly assigned anti-Helicobacter pylori triple therapy alone, calcium carbonate alone, or in combination with triple therapy, tetracycline, or placebo. We compared risk differences for posttreatment Helicobacter pylori status and increased reflux symptoms from crude, multivariable and stratified multivariable analyses. In crude analyses, 54% of subjects without Helicobacter pylori after-treatment reported an increase in reflux compared to 41% of those with persistent infection (risk difference = 13%; P = 0.07). Only subjects with multifocal atrophic gastritis assigned to calcium carbonate reported an increase in reflux symptoms more frequently when Helicobacter pylori was absent versus when it persisted (risk difference = 52%; P = 0.0001). Therefore, the interaction of calcium carbonate use, chronic multifocal atrophic gastritis, and the absence of Helicobacter pylori may increase reflux symptoms.