title: Vaccination and Risk for Developing Inflammatory Bowel Disease: A Meta-Analysis of Case-Control and Cohort Studies.
abstract: OBJECTIVE
  Environmental factors may play a key role in the pathogenesis of inflammatory bowel disease (IBD). Whether vaccination is associated causally with IBD is controversial. We performed a meta-analysis of case-control and cohort studies on the association between vaccination and the risk for IBD.
  
  
  METHODS
  Studies and abstracts investigating the relationship between vaccination and subsequent risk for developing IBD were reviewed. Childhood or adult immunizations with any vaccine type, at any dose, and with any vaccine schedule were used as inclusion criteria.
  
  
  RESULTS
  Eleven studies were included in the systematic review and meta-analysis: 8 case-control studies and 3 cohort studies. Studied vaccines were bacille Calmette-Guérin), vaccines against diphtheria, tetanus, smallpox, poliomyelitis, pertussis, H1N1, measles, rubella, mumps, and the combined measles, mumps, and rubella vaccine. Only a few details about vaccine type or route of administration were found in studies. Overall, there was no association between childhood immunization and risk for developing IBD: bacille Calmette-Guérin, relative risk (RR) of 1.04 (95% confidence interval [CI], 0.78-1.38), diphtheria, RR of 1.24 (95% CI, 0.80-1.94), tetanus, RR of 1.27 (95% CI, 0.77-2.08), smallpox, RR of 1.08 (95% CI, 0.70-1.67), poliomyelitis, RR of 1.79 (95% CI, 0.88-3.66), an measles containing vaccines, RR of 1.33 (95% CI, 0.31-5.80) in cohort studies, and RR of 0.85 (95% CI, 0.60-1.20) in case-control studies. Subgroup analysis for Crohn's disease (CD) and ulcerative colitis (UC) found an association between the poliomyelitis vaccine and risk for developing CD (RR, 2.28; 95% CI, 1.12-4.63) or UC (RR, 3.48; 95% CI, 1.2-9.71). The RR of developing IBD after H1N1 vaccination was 1.13 (95% CI, 0.97-1.32).
  
  
  CONCLUSIONS
  Results of this meta-analysis show no evidence supporting an association between childhood immunization or H1N1 vaccination in adults and risk of developing IBD. The association between the poliomyelitis vaccine and the risk for CD or UC should be analyzed with caution because of study heterogeneity.
authors.affiliation: Gastroenterology and Hepatology Department, Lille University Hospital, Lille, France; Lille Inflammation Research International Center LIRIC-UMR 995 Inserm, Université Lille 2, CHRU de Lille, Equipe IBD and Environmental Factors: Epidemiology and Functional Analyses, Lille University, Lille, France; Public Health, Epidemiology and Economic Health, Registre Epimad, Maison Régionale de la Recherche Clinique, Centre Hospitalier Universitaire Régional, Lille Cedex, France; Gastroenterology and Hepatology Department, Montpellier University Hospital, Montpellier, France. Electronic address: gpinetondechambrun@yahoo.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Pineton de Chambrun
authors.affiliation: Public Health, Epidemiology and Economic Health, Registre Epimad, Maison Régionale de la Recherche Clinique, Centre Hospitalier Universitaire Régional, Lille Cedex, France; Epidemiological Department, Lille University Hospital, Lille, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Dauchet
authors.affiliation: Gastroenterology and Hepatology Department, Lille University Hospital, Lille, France; Lille Inflammation Research International Center LIRIC-UMR 995 Inserm, Université Lille 2, CHRU de Lille, Equipe IBD and Environmental Factors: Epidemiology and Functional Analyses, Lille University, Lille, France; Public Health, Epidemiology and Economic Health, Registre Epimad, Maison Régionale de la Recherche Clinique, Centre Hospitalier Universitaire Régional, Lille Cedex, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Gower-Rousseau
authors.affiliation: Gastroenterology and Hepatology Department, Lille University Hospital, Lille, France; Lille Inflammation Research International Center LIRIC-UMR 995 Inserm, Université Lille 2, CHRU de Lille, Equipe IBD and Environmental Factors: Epidemiology and Functional Analyses, Lille University, Lille, France; Public Health, Epidemiology and Economic Health, Registre Epimad, Maison Régionale de la Recherche Clinique, Centre Hospitalier Universitaire Régional, Lille Cedex, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Cortot
authors.affiliation: Department of Gastroenterology, Icahn Medical School of Medicine at Mount Sinai, New York, New York.
authors.forename: Jean-Frédéric
authors.initials: JF
authors.lastname: Colombel
authors.affiliation: Public Health, Epidemiology and Economic Health, Registre Epimad, Maison Régionale de la Recherche Clinique, Centre Hospitalier Universitaire Régional, Lille Cedex, France; Inserm U954 and Department of Gastroenterology, Université de Lorraine, Nancy les Vandoeuvre, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Peyrin-Biroulet
mesh_terms: D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000139:chemically induced* / Q000453:epidemiology*; D018570:Risk Assessment; D014611:Vaccination / Q000009:adverse effects*
keywords: BCG; Childhood; Crohn’s Disease; Poliomyelitis; Ulcerative Colitis; Vaccine