title: Asthma is inversely associated with Helicobacter pylori status in an urban population.
abstract: BACKGROUND
  Microbial exposures have been suggested to confer protection from allergic disorders and reduced exposures to gastrointestinal microbiota have been proposed as an explanation for the increase in asthma prevalence. Since the general prevalence of Helicobacter pylori has been decreasing, we hypothesized that H. pylori serostatus would be inversely related to the presence of asthma.
  
  
  METHODS
  Adults were recruited to participate in the New York University (NYU)/Bellevue Asthma Registry in New York City. Adult asthma cases (N = 318) and controls (N = 208) were identified and serum IgG antibodies to H. pylori whole cell antigens or the immunodominant CagA antigen were measured.
  
  
  RESULTS
  As expected, the asthma cases and controls differed with respect to atopy and lung function. Seropositivity to H. pylori or CagA antigen was present in 47.1% of the total case and control study population. Asthma was inversely associated with CagA seropositivity (OR = 0.57, 95% CI = 0.36-0.89). Median age of onset of asthma (doctor's diagnosis) was older (21 years) among individuals with CagA+ strains than among H. pylori- individuals (11 years) (p = 0.006).
  
  
  CONCLUSIONS
  These data are consistent with the hypothesis that colonization with CagA+ H. pylori strains is inversely associated with asthma and is associated with an older age of asthma onset in an urban population. The data suggest H. pylori as a marker for protection.
authors.affiliation: Department of Medicine, New York University School of Medicine, New York City, New York, USA. reibmj01@gcrc.med.nyu.edu
authors.forename: Joan
authors.initials: J
authors.lastname: Reibman
authors.forename: Michael
authors.initials: M
authors.lastname: Marmor
authors.forename: Joshua
authors.initials: J
authors.lastname: Filner
authors.forename: Maria-Elena
authors.initials: ME
authors.lastname: Fernandez-Beros
authors.forename: Linda
authors.initials: L
authors.lastname: Rogers
authors.forename: Guillermo I
authors.initials: GI
authors.lastname: Perez-Perez
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Blaser
mesh_terms: D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000378:metabolism; D001249:Asthma / Q000150:complications* / Q000382:microbiology; D001426:Bacterial Proteins / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D016481:Helicobacter Infections / Q000150:complications* / Q000382:microbiology; D016480:Helicobacter pylori / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D013147:Spirometry; D014505:Urban Population
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G; C080866:cagA protein, Helicobacter pylori