ADHD News & Research

Study: Babies Exposed to Cigarette Smoke Exhibit Greater Conduct Problems in Childhood

The risks of smoking while pregnant are well documented. Now, new research shows a direct relationship between babies’ exposure to cigarette smoke during their first four years and the severity of their hyperactivity and conduct problems in First Grade.

January 13, 2020

The prenatal impacts of maternal smoking have been widely studied, but only recently did researchers show a linear relationship between postnatal exposure to cigarette smoke or residue and a heightened risk for hyperactivity and conduct problems in children. The new study, published last month in The Journal of Child Psychology and Psychiatry, found that the magnitude of cigarette smoke exposure within the first four years of life bore a direct relationship to a child’s symptoms of hyperactivity and conduct problems by First Grade.1

Researchers studied data from the Family Life Project for 1,096 children gathered at four distinct ages: 6, 15, 24, and 48 months of age. To quantify postnatal smoke exposure, they used salivary cotinine — the metabolic byproduct of nicotine exposure — which is a more precise tool to analyze smoke exposure than is parental self-reporting. Researchers also controlled the participant pool for possible confounds including family history of ADHD, caregiver IQ, caregiver symptoms of psychopathology, economic adversity, and obstetric problems.

To measure the child’s externalizing symptoms, the primary caregiver and the child’s First Grade teacher completed both the Disruptive Behavior Disorders Rating Scale and the Strengths and Difficulties Questionnaire.

Specifically, this study found that greater exposure to environmental nicotine — as evidenced by high cotinine levels in the children studied — was significantly associated with both hyperactivity and conduct problems in the First Grade. This linear association remained unchanged even after researchers excluded from the model mothers who smoked during pregnancy. Thus, this study shows that the postnatal period is a uniquely vulnerable period for neurobehavioral development.

Children may experience nicotine exposure in two distinct ways: direct second-hand exposure to cigarette smoke and exposure to nicotine residue that remains on the surfaces of commonplace things — such as toys, the floor, and parents’ clothes — with which children frequently physically interact. Thus, the potential for nicotine exposure extends well beyond the airborne phase and beyond the prenatal period.

Sources

Gatzke‐Kopp, L., Willoughby, M. T., Warkentien, S., Petrie, D., Mills‐Koonce, R., & Blair, C. (2019, December 03). Association between environmental tobacco smoke exposure across the first four years of life and manifestation of externalizing behavior problems in school‐aged children. Journal of Child Psychology and Psychiatry. doi:10.1111/jcpp.13157. Retrieved from: https://onlinelibrary.wiley.com/doi/full/10.1111/jcpp.13157

Updated on February 18, 2020

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