When is Helicobacter pylori acquired in populations in developing countries? A birth-cohort study in Bangladeshi children

ABSTRACT

Helicobacter pylori colonization is prevalent throughout the world, and is predominantly acquired during childhood. In developing countries, >70% of adult populations are colonized with H. pylori and >50% of children become colonized before the age of 10 years. However, the exact timing of acquisition is unknown. We assessed detection of H. pylori acquisition among a birth cohort of 105 children in Mirzapur, Bangladesh. Blood samples collected at time 0 (cord blood), and at 6, 12, 18, and 24 months of life were examined for the presence of IgG and IgA antibodies to whole cell H. pylori antigen and for IgG antibodies to the CagA antigen using specific ELISAs and immunoblotting. Breast milk samples were analyzed for H. pylori-specific IgA antibodies. Cord blood was used to establish maternal colonization status. H. pylori seroprevalence in the mothers was 92.8%. At the end of the two-year follow-up period, 50 (47.6%) of the 105 children were positive for H. pylori in more than one assay. Among the colonized children, CagA prevalence was 78.0%. A total of 58 children seroconverted: 50 children showed persistent colonization and 8 (7.6%) children showed transient seroconversion, but immunoblot analysis suggested that the transient seroconversion observed by ELISA may represent falsely positive results. Acquisition of H. pylori was not influenced by the mother H. pylori status in serum or breastmilk. In this population with high H. pylori prevalence, we confirmed that H. pylori in developing countries is detectable mainly after the first year of life.

Keywords:

• acquisition
• transmission
• epidemiology
• developing countries
• CagA
• seroprevalence
• seroconversion
• breast feeding
• serological diagnostic testing

Acknowledgments

We dedicate this paper to the memory of our colleague, R. Bradley Sack, M.D., Ph.D., who sadly did not survive until its publication. We remember Brad as a dedicated scientist and a great friend.

Contributors

GIPP and MJB designed the study. SK, GIPP, AZP, PB, SAS, KZH, and RBS collected samples and performed experiments. SK and GIPP analyzed the data. SK, GIPP, and MJB wrote the paper. All authors have read and were involved in critical revisions of the final paper.

Competing interest

None declared.

Ethics approval.

Each reporting center gave local approval as mentioned in text.

Additional information

Funding

HHS | NIH | National Center for Research rdf:resources (NCRR), P60 MD000538 HHS | NIH | National Center for Research rdf:resources (NCRR), RO1 GM63270 C&D Fund NYU Center for the study of Asian American Health Thrasher Reserach Fund Award, 02816-9.