Association between environmental tobacco smoke exposure in early life and autistic-like behaviors in Chinese preschoolers.

OBJECTIVE: Few studies have evaluated the association between children's exposure to environmental tobacco smoke (ETS) in early life (during pregnancy, from birth to one year and from one to three years) and autistic-like behaviors. This study aimed to explore this association. METHODS: This cross-sectional study analyzed data collected in 2017 as part of the Longhua Child Cohort Study. Autistic-like behaviors were measured using the Autism Behavior Checklist (ABC). Data on ETS exposure and autistic-like behaviors of children were collected via self-administered questionnaires completed by the mothers. Multivariate logistic regression models were undertaken to assess the associations. RESULTS: Of the 65,243 participants included in this study, 1958 children met criteria for having autistic-like behaviors. The results showed that children were more likely to exhibit autistic-like behaviors when they were exposed to ETS in early life (AOR = 1.38; 95% CI = 1.26-1.52), compared to preschoolers without ETS exposure at any period of their early life. Compared with their unexposed counterparts, children who were exposed to ETS during gestation (AOR = 1.42; 95% CI = 1.29-1.57), or from birth to one year old (AOR = 1.42; 95% CI = 1.19-1.69) had significantly increased risk of autistic-like behaviors. In addition, with the increase in duration of exposure and average number of cigarettes smoked in the child's immediate environment, the risk of autistic-like behaviors increased. CONCLUSION: Our study indicated that children's ETS exposure in early life was significantly associated with autistic-like behaviors. When children's exposure to cigarettes in early life increased in duration and number, the likelihood of the presence of autistic-like behaviors was higher.