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.

Extremely Preterm Born Children at Very High Risk for Developing Autism Spectrum Disorder

“…Studies also suggest a link between extreme prematurity and autism spectrum disorder (ASD), characterised by persistent deficits in social communication and social interaction, and restrictive and repetitive patterns of behaviours, interests or activities (10). Prematurity and low birth weight are considered to be risk factors for ASD (11)(12)(13)(14)(15)(16)(17). Two recent studies even found a gradual increased risk of traits of ASD with shorter gestation (18,19).…”

The association between the interpregnancy interval and autism spectrum disorder in a Canadian cohort

“…6,7 Separate logistic regression models were fit for each case group to estimate crude and adjusted odds ratios (ORs) for ASD in the second-born children, using the same comparison group in each model. A priori, we decided to include the following covariates in the models due to previously documented associations with ASD: child's sex, birth year (we mean-centered this variable and created a quadratic term to account for birth year's non-linear association with ASD in our cohort), and presence of an intellectual disability (defined as a "Multiple Handicaps" special needs code in the Education data, or the presence of various diagnostic codes in the Medical Services or Hospital Discharge Abstracts databases 18 ), as well as maternal age at delivery (<30, 30-34, ≥35 years [19][20][21] ) and whether the mother had ever received income assistance. In a supplementary analysis, we added product terms to the regression models to explore whether certain factors interacted with the IPI to modify the association.…”

Genetic testing in autism: how much is enough?

“…In addition, several parents reported that they or members of their extended family had learning disabilities, speech delay or dyslexia, or mental retardation. A "broader autism phenotype" (BAP), [37][38][39] in which core components of an ASD may be present in milder form, as well as a range of psychiatric diagnoses, 40,41 have been described previously in parents and extended family members in ASD pedigrees. The presence of the BAP was not formally assessed in parents during clinical genetics evaluations.…”