Secondhand Smoke Linked to ADHD, Learning Disabilities

In what is being billed as the first study to examine common child neurobehavioral disorders in relation to secondhand smoke (SHS) exposure in the home, researchers reported that the odds of two or three parent-reported child neurobehavioral disorders increased by 50% and the need for treatment or counseling also increased in homes where children were exposed to SHS.

“The findings of the study, which are associational and not necessarily causal, underscore the health burden of childhood neurobehavioral disorders that may be attributable to SHS exposure in homes in the United States,” the authors wrote in the study, which was published recently in Pediatrics. The study was conducted by the Free Research Institute in Dublin, Ireland, and the Center for Global Tobacco Control at the Harvard School of Public Health in Boston.

Researchers used the 2007 National Survey on Children’s Health, which was conducted by the Centers for Disease Control and Prevention, to determine the association between parent-reported postnatal SHS exposure in the home and neurobehavioral disorders such as attention-deficit/hyperactivity disorder, learning disabilities, and conduct disorders among children younger than 12 years in the United States.

“The methods used in this study were multivariable logistic regression models that accounted for potential confounders and complex survey designs to evaluate associations,” the authors wrote.

The data indicated that a total of 6% of 55,358 children, corresponding to a weighted total of 4.8 million children across the United States, were exposed to SHS in the home. “The weighted prevalence and 95% confidence intervals of each of the children’s neurobehavioral outcomes were 8.2% (7.5—8.8) with learning disabilities, 5.9% (5.5–6.4) with attention-deficit/hyperactivity disorder, and 3.6% (3.1–4.0) with behavioral and conduct disorders,” the authors wrote.

The researchers added that children exposed to SHS at home had a 50% increased odds of having more than two childhood neurobehavioral disorders compared with children who were not exposed to SHS. Boys had a significantly higher risk.

“Older children, especially those aged nine to 11 years, and those living in households with the highest poverty levels were at greater risk. In absolute terms, 274,100 excess cases in total of these three disorders could have been prevented if children had not been exposed to SHS in their homes,” the researchers concluded.

“These health and economic burdens might be reduced significantly if voluntary smoke-free home policies are vigorously encouraged. Nevertheless, additional evidence is warranted in additional population settings for entirely evidence-based health policy decision making.”