title: Risk factors for autism: perinatal factors, parental psychiatric history, and socioeconomic status.
abstract: Research suggests that heredity and early fetal development play a causal role in autism. This case-control study explored the association between perinatal factors, parental psychiatric history, socioeconomic status, and risk of autism. The study was nested within a cohort of all children born in Denmark after 1972 and at risk of being diagnosed with autism until December 1999. Prospectively recorded data were obtained from nationwide registries in Denmark. Cases totaled 698 children with a diagnosis of autism; each case was individually matched by gender, birth year, and age to 25 controls. Analyses by conditional logistic regression produced risk ratios and 95% confidence intervals. Adjusted analyses showed that the risk of autism was associated with breech presentation (risk ratio (RR) = 1.63, 95% confidence interval (CI): 1.18, 2.26), low Apgar score at 5 minutes (RR = 1.89, 95% CI: 1.10, 3.27), gestational age at birth <35 weeks (RR = 2.45, 95% CI: 1.55, 3.86), and parental psychiatric history (schizophrenia-like psychosis: RR = 3.44, 95% CI: 1.48, 7.95; affective disorder: RR = 2.91, 95% CI: 1.65, 5.14). Analyses showed no statistically significant association between risk of autism and weight for gestational age, parity, number of antenatal visits, parental age, or socioeconomic status. Results suggest that prenatal environmental factors and parental psychopathology are associated with the risk of autism. These factors seem to act independently.
authors.affiliation: North Atlantic Neuro-Epidemiology Alliances, Department of Epidemiology and Social Medicine, University of Aarhus, Aarhus, Denmark.
authors.forename: Heidi Jeanet
authors.initials: HJ
authors.lastname: Larsson
authors.forename: William W
authors.initials: WW
authors.lastname: Eaton
authors.forename: Kreesten Meldgaard
authors.initials: KM
authors.lastname: Madsen
authors.forename: Mogens
authors.initials: M
authors.lastname: Vestergaard
authors.forename: Anne Vingaard
authors.initials: AV
authors.lastname: Olesen
authors.forename: Esben
authors.initials: E
authors.lastname: Agerbo
authors.forename: Diana
authors.initials: D
authors.lastname: Schendel
authors.forename: Poul
authors.initials: P
authors.lastname: Thorsen
authors.forename: Preben Bo
authors.initials: PB
authors.lastname: Mortensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D001321:Autistic Disorder / Q000453:epidemiology* / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016001:Confidence Intervals; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D008487:Medical History Taking / Q000706:statistics & numerical data*; D001523:Mental Disorders / Q000453:epidemiology* / Q000235:genetics*; D016017:Odds Ratio; D010290:Parents; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D015995:Prevalence; D012307:Risk Factors; D012959:Socioeconomic Factors