Prenatal and Postnatal Secondhand Smoking Exposure on Adolescents' Externalizing Behavior

China is the world's largest consumer and producer of tobacco, with 53% of men smoking. Increasing evidence implicates prenatal exposure to smoking as a risk factor for child externalizing behavior problems (aggression, ADHD, rule breaking and delinquency), which is in turn an important risk factor for smoking initiation later in life. In contrast to this active smoking, there is far less research on the effects of second-hand smoking exposure (SHS), a form of passive smoking defined as the inhalation of tobacco by persons other than the intended ‘active’ smoker. While prenatal active smoking exposure is associated with cognitive and emotional risk factors for externalizing behavior, much less in known on the effects of SHS on cognitive and emotional functioning. The main aims of this study are: (1) to investigate whether prenatal SHS exposure is associated with the development of externalizing behavior in adolescence, controlling for parental externalizing behavior and (2) test whether cognitive and emotional abnormalities mediate the SHS - externalizing behavior relationship. This proposal builds on the PI’s large prospective cohort study previously funded by an NIH R01 award, which focused on lead exposure. This project focuses on secondhand smoking exposure and adolescents' behavior. Our pilot work from this cohort indicated that prenatal SHS exposure has effects on externalizing behavior in children at age 6, but we do not know if there are long-term effects, and we do not know the mechanism of action. The proposed study will help address these unresolved questions. The original epidemiological sample consisted of over 1,000 3-5 year-old Chinese children who are now in high school. We propose to make use of data that we already collected on prenatal and postnatal SHS exposure, pyschophysiology, neurocognitive and emotion, and will collect data on adolescents' IQ, school performance, and externalizing behavior. The interdisciplinary research team, consisting of researchers across three Penn schools and collaborators in China, has decades of experience in studying child behavior problems, psychophysiology, and smoking. We believe this would be the first study to assess the effect of prenatal SHS exposure on adolescent externalizing behavior in conjunction with neurobiological mediating factors. Findings may help build public awareness and support for further prevention efforts for reducing SHS and consequent behavior problems. It will also provide basis for a future NIH grant to investigate whether long-term SHS has an impact on adolescent’s smoking initiation.