title: Toxoplasma infection and later development of schizophrenia in mothers.
abstract: OBJECTIVE
  Several studies based on clinical samples have found an association between Toxoplasma gondii infection and schizophrenia, and a case-control study among U.S. military personnel with specimens available from both before and after diagnosis found a positive association between T. gondii immunoglobulin G (IgG) antibody level and schizophrenia. These findings have never been replicated in a prospective cohort study. The purpose of this study was to determine whether mothers infected with T. gondii have an elevated risk of schizophrenia or related disorders and whether the risk depends on IgG antibody level.
  
  
  METHODS
  In a register-based prospective cohort study of 45,609 women born in Denmark, the level of T. gondii-specific IgG antibodies was measured in connection with childbirth between 1992 and 1995. Women were followed up from the date of delivery until 2008.
  
  
  RESULTS
  A significant positive association between T. gondii IgG antibody level and schizophrenia spectrum disorders was found. Mothers with the highest IgG level had a relative risk of 1.73 (95% confidence interval [CI]=1.12-2.62) compared with mothers with the lowest IgG level. For schizophrenia, the relative risk was 1.68 (95% CI=0.77-3.46). When the mothers were classified according to IgG level, only those with the highest IgG levels had a significantly higher risk of schizophrenia spectrum disorders.
  
  
  CONCLUSIONS
  Women with high levels of T. gondii-specific IgG antibodies have a significantly elevated risk of developing schizophrenia spectrum disorders.
authors.affiliation: National Center for Register-Based Research, Aarhus University, Denmark. mgp@ncrr.dk
authors.forename: Marianne Giørtz
authors.initials: MG
authors.lastname: Pedersen
authors.forename: Hanne
authors.initials: H
authors.lastname: Stevens
authors.forename: Carsten Bøcker
authors.initials: CB
authors.lastname: Pedersen
authors.forename: Bent
authors.initials: B
authors.lastname: Nørgaard-Pedersen
authors.forename: Preben Bo
authors.initials: PB
authors.lastname: Mortensen
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003718:Denmark; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology / Q000523:psychology*; D011446:Prospective Studies; D012306:Risk; D012559:Schizophrenia / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D014122:Toxoplasma / Q000276:immunology; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology / Q000523:psychology*; D014125:Toxoplasmosis, Congenital / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology / Q000523:psychology; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G