Effects of Helicobacter pylori, geohelminth infection and selected commensal bacteria on the risk of allergic disease and sensitization in 3-year-old Ethiopian children

Clin Exp Allergy. 2011 Oct;41(10):1422-30. doi: 10.1111/j.1365-2222.2011.03831.x. Epub 2011 Aug 10.


Background: Epidemiological studies have suggested that gastro-intestinal infections including Helicobacter pylori, intestinal microflora (commensal bacteria) and geohelminths may influence the risk of asthma and allergy but data from early life are lacking.

Objective: We aimed to determine the independent effects of these infections on allergic disease symptoms and sensitization in an Ethiopian birth cohort.

Methods: In 2008/09, 878 children (87% of the 1006 original singletons in a population-based birth cohort) were followed up at age 3 and interview data obtained on allergic symptoms and potential confounders. Allergen skin tests to Dermatophagoides pteronyssinus and cockroach were performed, levels of Der p 1 and Bla g 1 in the child's bedding measured and stool samples analysed for geohelminths and, in a random subsample, enterococci, lactobacilli, bifidobacteria and H. pylori antigen. The independent effects of each exposure on wheeze, eczema, hayfever and sensitization were determined using multiple logistic regression.

Results: Children were commonly infected with H. pylori (41%; 253/616), enterococci (38.1%; 207/544), lactobacilli (31.1%; 169/544) and bifidobacteria (18.9%; 103/544) whereas geohelminths were only found in 8.5% (75/866). H. pylori infection was associated with a borderline significant reduced risk of eczema (adjusted OR 0.49, 95% CI 0.24-1.01, P=0.05) and D. pteronyssinus sensitization (adjusted OR 0.42, 95% CI 0.17-1.08, P=0.07). Geohelminths and intestinal microflora were not significantly associated with any of the outcomes measured.

Conclusion and clinical relevance: Among young children in a developing country, we found evidence to support the hypothesis of a protective effect of H. pylori infection on the risk of allergic disease. Further investigation of the mechanism of this effect is therefore of potential therapeutic and preventive value.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Allergens / immunology
  • Animals
  • Ascaris / immunology
  • Bacteria / immunology*
  • Child, Preschool
  • Cohort Studies
  • Eczema / diagnosis
  • Eczema / immunology
  • Ethiopia / epidemiology
  • Female
  • Helicobacter Infections / epidemiology*
  • Helicobacter Infections / immunology
  • Helicobacter Infections / microbiology
  • Helicobacter pylori / immunology*
  • Helminthiasis / epidemiology*
  • Helminthiasis / immunology
  • Helminthiasis / parasitology
  • Helminths / immunology*
  • Humans
  • Hypersensitivity / diagnosis
  • Hypersensitivity / epidemiology*
  • Hypersensitivity / immunology
  • Middle Aged
  • Risk Factors
  • Skin Tests
  • Young Adult


  • Allergens