title: Association between Helicobacter pylori and asthma: a meta-analysis.
abstract: OBJECTIVE
  Helicobacter pylori infection is recognized as a worldwide public health threat. Some studies have suggested that individuals with asthma have a lower rate of H. pylori infection, but the relation remains controversial. This meta-analysis was carried out to quantify the association between H. pylori infection and asthma.
  
  
  METHODS
  Published information on the prevalence of H. pylori in individuals with asthma was collected to assess the potential associations between H. pylori infection and the risk of asthma. Fourteen eligible studies were selected for analysis. Data on the study populations, detection method of H. pylori, and publication year were summarized. Meta-regression models and subgroup analyses were established to screen the factors resulting in heterogeneity.
  
  
  RESULTS
  Of the 106 articles retrieved, 14 fulfilled the inclusion criteria. The 14 studies involved 28 283 patients, with a total H. pylori infection rate of 40.53%. This meta-analysis found a significantly lower rate of H. pylori infection in the asthmatics than in the controls (odds ratio=0.84, 95% confidence interval: 0.73-0.96, P=0.013). Subgroup analysis indicated a similar infection rate of CagA-positive H. pylori infection in the asthmatic group and the control group (odds ratio=0.73, 95% confidence interval: 0.41-1.28, P=0.03).
  
  
  CONCLUSIONS
  The pooled data suggest that asthmatics have a significantly lower rate of H. pylori infection. Large-scale and multicenter studies should be carried out to further determine the relation between this bacterium and allergic disorders.
authors.affiliation: Department of Gastroenterology, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Zhou
authors.forename: Junbei
authors.initials: J
authors.lastname: Wu
authors.forename: Guoxin
authors.initials: G
authors.lastname: Zhang
mesh_terms: D001249:Asthma / Q000150:complications / Q000453:epidemiology* / Q000517:prevention & control; D016481:Helicobacter Infections / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D015995:Prevalence