title: Effects of Helicobacter pylori, geohelminth infection and selected commensal bacteria on the risk of allergic disease and sensitization in 3-year-old Ethiopian children.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia. alamwo1@yahoo.com
authors.forename: A
authors.initials: A
authors.lastname: Amberbir
authors.forename: G
authors.initials: G
authors.lastname: Medhin
authors.forename: W
authors.initials: W
authors.lastname: Erku
authors.forename: A
authors.initials: A
authors.lastname: Alem
authors.forename: R
authors.initials: R
authors.lastname: Simms
authors.forename: K
authors.initials: K
authors.lastname: Robinson
authors.forename: A
authors.initials: A
authors.lastname: Fogarty
authors.forename: J
authors.initials: J
authors.lastname: Britton
authors.forename: A
authors.initials: A
authors.lastname: Venn
authors.forename: G
authors.initials: G
authors.lastname: Davey
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology; D000818:Animals; D001200:Ascaris / Q000276:immunology; D001419:Bacteria / Q000276:immunology*; D002675:Child, Preschool; D015331:Cohort Studies; D004485:Eczema / Q000175:diagnosis / Q000276:immunology; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D016481:Helicobacter Infections / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology; D016480:Helicobacter pylori / Q000276:immunology*; D006373:Helminthiasis / Q000453:epidemiology* / Q000276:immunology / Q000469:parasitology; D006376:Helminths / Q000276:immunology*; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D008875:Middle Aged; D012307:Risk Factors; D012882:Skin Tests; D055815:Young Adult
chemical_list: D000485:Allergens