Risk Factors for Autism: Perinatal Factors, Parental Psychiatric History, and Socioeconomic Status

TLDR

Autism is believed to arise from genetic and early fetal developmental factors. The study aimed to examine how perinatal factors, parental psychiatric history, and socioeconomic status influence autism risk. The authors conducted a nested case‑control study within a Danish birth cohort, matching 698 autism cases to 25 controls each by gender, birth year, and age, and used nationwide registry data with conditional logistic regression to estimate risk ratios. Breech presentation, low Apgar score, preterm birth (<35 weeks), and parental psychiatric history (schizophrenia‑like psychosis and affective disorder) were associated with increased autism risk, whereas weight for gestational age, parity, antenatal visits, parental age, and socioeconomic status showed no significant association, indicating independent effects of prenatal environmental factors and parental psychopathology.

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.