title: Helicobacter pylori infection and atopic diseases: is there a relationship? A systematic review and meta-analysis.
abstract: OBJECTIVE
  To review and conduct a meta-analysis of the existing literature on the relationship between Helicobacter pylori (H. pylori), atopy and allergic diseases.
  
  
  METHODS
  Studies published in English assessing the prevalence of atopy and/or allergic diseases in patients with H. pylori infection and the prevalence of H. pylori infection in patients with atopy and/or allergic diseases were identified through a MEDLINE search (1950-2014). Random-effect model was used for the meta-analysis.
  
  
  RESULTS
  Pooled results of case-control studies showed a significant inverse association of H. pylori infection with atopy/allergic disease or with exclusively atopy, but not with allergic disease, whereas pooled results of cross-sectional studies showed only a significant association between allergic disease and H. pylori infection.
  
  
  CONCLUSIONS
  There is some evidence of an inverse association between atopy/allergic diseases and H. pylori infection, although further studied are needed.
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Lionetti
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Leonardi
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Lanzafame
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Garozzo
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Filippelli
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Tomarchio
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Viviana
authors.initials: V
authors.lastname: Ferrara
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Salpietro
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Pulvirenti
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Ruggiero
authors.initials: R
authors.lastname: Francavilla
authors.affiliation: Elena Lionetti, Salvatore Leonardi, Angela Lanzafame, Maria Teresa Garozzo, Martina Filippelli, Stefania Tomarchio, Viviana Ferrara, Department of Pediatrics, University of Catania, 95100 Catania, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Catassi
mesh_terms: D016481:Helicobacter Infections / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D016017:Odds Ratio; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors
keywords: Allergic diseases; Atopy; Helicobacter pylori; Hygiene hypothesis; Infection