Children with asthma regularly exposed to secondhand smoke are more likely to have sleep problems, including difficulty falling asleep, more sleep-disordered breathing and increased daytime sleepiness, according to a new study in the February issue of Pediatrics.
"The consequences of inadequate sleep in children are not trivial,” says Kimberly Yolton, Ph.D., an environmental health researcher at Cincinnati Children’s and the study’s main author. "Sleep disturbances have been linked with increased behavior problems, mental health problems and poor school performance. A reduction in exposure to secondhand smoke has the potential to significantly impact the physical and emotional health of children with asthma.”
Yolton and her research colleagues examined 219 children enrolled in the Cincinnati Asthma Prevention Study. Participants were between the ages of 6 and 12, had physician-diagnosed asthma and had been treated for it within the previous year. Their parents reported that their children had been exposed to secondhand smoke at home from at least five cigarettes a day.
The researchers also measured serum cotinine -- a substance produced when the body breaks down nicotine. Cotinine provides a scientific assessment of tobacco exposure. By that measure, children in the study were exposed to a median of 13 cigarettes a day in their homes.
"As secondhand smoke exposure increased, parents reported longer delays in their children falling asleep; more frequent parasomnias, such as nightmares, night terrors and sleepwalking; more sleep disordered breathing; increased daytime sleepiness; and greater overall sleep disturbance,” says Yolton. "93 percent of those studied had a sleep disturbance score that would be considered clinically relevant, and the severity of the reported problems increased with greater exposure to tobacco smoke.”
Since all children in the study had asthma, the findings may not apply to children without asthma, according to Yolton.
The study was funded by grants from the National Institutes of Health.