Smoke exposure may contribute to childhood learning disorders

Share this content:

Secondhand exposure to cigarette smoke increased childhood risk for neurobehavioral disorders 50% compared with no exposure, data from a nationally representative survey indicate.

"This is particularly significant with regard to the potential burden of pediatric mental health care on an overextended health care system, a problem that could be dramatically reduced if voluntary smoke-free home policies were widely adopted," Hillel R. Alpert, ScM, of the Harvard School of Public Health in Boston, and colleagues wrote in Pediatrics.

They analyzed data from the telephone-based National Survey of Children's Health, conducted between April 2007 and July 2008. The survey sample included 91,642 children from birth through 17 years of age, with an average sample size of about 1,800 children per state. Data from 55,358 children younger than 12 years were included in the analysis.

In 2007, a total of 5.5 million children resided in a home in which someone smoked, the researchers determined.

Among these children, the weighted prevalence of learning disabilities was 8.2% (95% CI: 7.5-8.8); attention deficit hyperactivity disorder/ attention deficit disorder (ADHD/ADD) was 5.9% (95% CI: 5.5-6.4) and conduct disorder prevalence was 3.6% (95% CI: 3.1-4).

These rates translate to an overall 50% increased risk for neurobehavioral disorder in a multivariable adjusted analysis compared with children who did not reside with smokers, according to the researchers.

Secondhand smoke exposure was also associated with a 50% increased risk for having two or more of the neurobehavioral disorders, and needing treatment or counseling for the disorder, data indicated.

Additional findings indicated that boys were at higher risk than girls for each disorder: ADHD/ADD (OR= 2.52; 95% CI: 2.24-2.83); learning disabilities (OR 1.80; 95% CI: 1.61-2); and conduct disorders (OR 2.73; 95% CI: 2.31-3.24).

This elevated risk was also observed among children aged 9 to 11 years: the odds ratio (OR) for ADHD/ADD was 18.20 (95% CI: 8.34-39.9); the OR for learning disabilities was 2.16 (95% CI: 1.59-2.91); and the OR for conduct disorders was 4.73 (95% CI: 2.31-9.67) in this population.

Several socioeconomic and sociodemographic factors appeared to influence the effects of secondhand smoke on these disorders, the researchers observed. For example, children who were exposed to secondhand smoke and belonged to the group at the highest poverty level had a 22% increased risk for learning disabilities, whereas children whose mothers had higher levels of education and those who lived with both parents had a lower likelihood of developing neurobehavioral disorders.

One possible solution to reduce secondhand smoke exposure in vulnerable populations would be to require public housing authorities to implement smoke-free policies, the researchers wrote. But they noted that more research is needed, as the relationship between secondhand smoke and neurobehavioral disorders observed in this study is associational and not casual.

Other factors including lead exposure, maternal smoking during pregnancy and child's current smoking status are potential unmeasured confounding factors, the researchers acknowledged. "Additional evidence is warranted in additional population settings for entirely evidence-based health policy decision making," the researchers wrote.

Children exposed to secondhand  cigarette smoke had a 50% increased risk for neurobehavioral disorders compared with those with no exposure, data from a nationally representative survey indicate.

"This is particularly significant with regard to the potential burden of pediatric mental health care on an overextended health care system, a problem that could be dramatically reduced if voluntary smoke-free home policies were widely adopted," Hillel R. Alpert, ScM, of the Harvard School of Public Health in Boston, and colleagues wrote in Pediatrics.

They analyzed data from the telephone-based National Survey of Children's Health, conducted between April 2007 and July 2008. The survey sample included 91,642 children from birth through 17 years of age, with an average sample size of about 1,800 children per state. Data from 55,358 children younger than 12 years were included in the analysis.

Kabir Z et al. Pediatrics. 2011;doi:10.1542/peds.2011-0023.

You must be a registered member of Clinical Advisor to post a comment.

Sign Up for Free e-newsletters