The Association between Autism Spectrum Disorders and Secondhand Tobacco Exposure

Second hand tobacco smoke exposure has been associated with neurobehavioral disorders among children. The objective of this study was to evaluate the relationship between second hand smoking and autism spectrum disorders (ASD) in children in the United States. Parent-reported postnatal tobacco exposure inside and outside the house and ASD diagnosis was examined in children younger than 12 years using the 2011-2012 National Survey on Children's Health. The physician diagnosis of current ASD as reported by the parents was used as the outcome variable. Univariate and multivariate logistic regression models adjusted for potential confounders were used to assess the associations. Of the 43,418 children, 23.6% had second hand smoke exposure, and 4.8% were exposed to tobacco smoke exposure inside the house (p-value <0.001). The mean age of children suffering from ASD in this study population was 6.5 years. In univariate logistic regression analysis, second hand tobacco exposure was associated with 36% greater odds of being diagnosed with ASD (p-value <0.001) and 39% greater odds of being diagnosed with ASD (p-value <0.001) if parents smoked inside the house. After adjusting for covariates, smoking (inside and outside the house) was not significantly associated with ASD risk in children. The prenatal, perinatal and other demographic factors are important predisposing factors for ASD in children and affect the relationship between second hand smoking and ASD.