Natural History of Helicobacter pylori Infection in Mexican Schoolchildren

Abstract

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.

The Prevalence of Helicobacter pylori Infection in Symptomatic Children: A 13-Year Observational Study in the Lower Silesian Region

“…A high rate of infection in adults was observed in the years 2009-2012 in six Latin American countries: Chile, Columbia, Costa Rica, Honduras, Mexico and Nicaragua (75--83%), without a drop in the prevalence of H. pylori infection in young people [17]. In Mexico City, among children aged 6-23 years, the incidence of H. pylori infection in the period from 2005 to 2010 was 38% [18]. In Europe, a much lower incidence of infection in children aged 3-15 years was reported: Czech Republic 4.5%, Sardinia, Italy 13.3% and Rome 8.7% [18,19].…”

“…In Mexico City, among children aged 6-23 years, the incidence of H. pylori infection in the period from 2005 to 2010 was 38% [18]. In Europe, a much lower incidence of infection in children aged 3-15 years was reported: Czech Republic 4.5%, Sardinia, Italy 13.3% and Rome 8.7% [18,19]. In Poland, the epidemiological data are based mainly on a multicenter study of 3435 children conducted in 2002.…”

Serologic Evidence for Fecal–Oral Transmission of Helicobacter pylori

“…38 Moreover, natural history studies have noted high rates of spontaneous clearance. 39,40 The decline in detectable H. pylori antibodies after infection clearance may result in misclassification of true prior H. pylori exposure and reduce concurrence with HAV seropositivity. Because H. pylori infection is thought to occur early in life and clearance or treatment may occur later in life, this may explain the divergence between H. pylori and HAV seroprevalence in older age groups (Figure 1) and the low agreement in positive serology.…”

Antral atrophy, intestinal metaplasia, and preneoplastic markers in Mexican children with Helicobacter pylori–positive and Helicobacter pylori–negative gastritis

“…Infection with H. pylori is highly prevalent among socially and economically disadvantaged children. Age, overcrowding, number of siblings, and a low maternal education level increase infection risk 4-7 .…”

“…Secondly, since Caudal Type Homeobox 2 (CDX2) expression precedes the development of gastric preneoplastic lesions in the setting of IM, we sought to define the H. pylori status and expression of CDX2 in our cohort of children and compare them with Mexican and American adult cohorts. Finally, we seek a panel of candidate biomarkers to use routinely in gastric biopsies in pediatric populations with a high prevalence of H. pylori infection 7 . Therefore, we selected an immunohistochemical (IHC) protein profile involved in gastric carcinogenesis and progression: Caudal Type Homeobox 2 10 , Ephrin Type-B Receptor 4 (EphB4) 11-12 , Matrix Metalloproteinase 3 (MMP3) 13-14 , Macrophage Migration Inhibitory Factor (MIF) 15 , p53 (TP53 tumor ressor gene) 16 , β-catenin, and E-cadherin 17-18 .…”