WEDNESDAY, Dec. 10, 2008 (HealthDay News) -- Secondhand smoke in the home increases the risk of behavioral problems in boys with asthma, researchers report.
The study, by a team at Cincinnati Children's Hospital Medical Center, included 220 boys and girls ages 6 to 12, with asthma.
For each doubling of secondhand smoke exposure, boys showed a twofold increase in behavioral problems such as hyperactivity, aggression, and depression.
The researchers found that secondhand smoke had no impact on girls, even though they were on average exposed to higher levels of tobacco smoke than boys. Additional research is needed to explain this gender difference, the researchers said.
The study was published online in the Journal of Developmental & Behavioral Pediatrics.
"These findings should encourage us to make stronger efforts to prevent childhood exposure to tobacco smoke, especially among higher risk populations, such as children with asthma," study lead author Kimberly Yolton, a researcher at the Children's Environmental Health Center at Cincinnati Children's, said in a hospital news release.
It's not known why secondhand smoke can cause behavioral problems in boys with asthma, but Yolton noted that there's "quite a bit of evidence" that nicotine in tobacco smoke affects development and functioning of the nervous system, as well as child development and behavior.
The children in this study were exposed to secondhand smoke from an average of 13 cigarettes a day, said the researchers, who added that even low levels of secondhand smoke exposure may lead to behavioral problems.
The Nemours Foundation has more about smoking and childhood asthma.