title: Maternal autoimmune diseases, asthma and allergies, and childhood autism spectrum disorders: a case-control study.
abstract: OBJECTIVE
  To investigate the association between physician-documented diagnoses of maternal autoimmune diseases, allergies, and asthma around the time of pregnancy and subsequent diagnoses of autism in children.
  
  
  METHODS
  A case-control study nested within a cohort of infants born between January 1995 and June 1999.
  
  
  METHODS
  Northern California Kaiser Permanente Medical Care Program.
  
  
  METHODS
  Cases (n = 420) were children with at least 1 diagnosis of an autism spectrum disorder (ASD) recorded in Kaiser Permanente outpatient clinical databases. Controls (n = 2100) were children without an ASD diagnosis who were frequency matched to cases on sex, birth year, and hospital of birth.
  
  
  METHODS
  Frequencies of maternal immunologic disorders were compared between cases and controls with a chi2 statistic, and relative risks were estimated by crude and adjusted odds ratios and 95% confidence intervals using logistic regression.
  
  
  RESULTS
  The final study population included 407 cases and 2095 controls. A similar proportion of case and control mothers had a diagnosis of any autoimmune disease in the 4-year period surrounding pregnancy (10.3% vs 8.2%, P = .15). After adjustment for maternal factors, only 1 autoimmune condition, psoriasis, was significantly associated with ASDs (adjusted odds ratio, 2.7; 95% confidence interval, 1.3-5.8). A greater than 2-fold elevated risk of ASD was observed for maternal asthma and allergy diagnoses recorded during the second trimester of pregnancy.
  
  
  CONCLUSIONS
  These findings suggest that maternal autoimmune disorders present in women around the time of pregnancy are unlikely to contribute significantly to autism risk. Further etiologic investigations are needed to confirm these results and should include objective documentation of diagnoses and consider a larger set of maternal immune-related conditions, including asthma and allergies.
authors.affiliation: Division of Research, Kaiser Foundation Research Institute, Kaiser Permanente, Oakland, Calif. 94612, USA. Lisa.A.Croen@kp.org
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Croen
authors.forename: Judith K
authors.initials: JK
authors.lastname: Grether
authors.forename: Cathleen K
authors.initials: CK
authors.lastname: Yoshida
authors.forename: Roxana
authors.initials: R
authors.lastname: Odouli
authors.forename: Judy
authors.initials: J
authors.lastname: Van de Water
mesh_terms: D001249:Asthma / Q000453:epidemiology / Q000276:immunology*; D001321:Autistic Disorder / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology; D001327:Autoimmune Diseases / Q000453:epidemiology / Q000276:immunology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000276:immunology*; D016015:Logistic Models; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology / Q000276:immunology*; D012306:Risk; D013997:Time Factors