ANN ARBOR, MI – Children who snore often are nearly twice as likely as other children to have attention and hyperactivity problems, and the link is strong for other sleep problems, a new University of Michigan Health System study finds. The results, published in the March issue of the journal Pediatrics, provide some of the most solid evidence ever of a link between sleep problems and behavior.
The link is strongest in boys under 8 years of age; habitual snorers in this group were more than three times more likely than non-snorers to be hyperactive. The study, based on a survey of the parents of 866 children that was conducted in the waiting rooms of U-M pediatrics clinics, is among the largest ever to explore the connection between sleep and inattention/hyperactivity.
While the study does not provide any clues as to whether and how sleep problems might contribute to behavior issues, or vice versa, the evidence of a link between the two is strong enough to warrant further and thorough investigation, says lead author Ronald Chervin, M.D., M.S., director of the Michael S. Aldrich Sleep Disorders Laboratory and associate professor of neurology at the U-M Medical School.
“If there is indeed a cause-and-effect link, sleep problems in children could represent a major public health issue,” says Chervin. “It’s conceivable that by better identifying and treating children’s snoring and other nighttime breathing problems, we could help address some of the most common and challenging childhood behavioral issues. But more research will be necessary to show whether this is the case.”
Until then, he suggests, all parents should pay attention to their children’s sleep behaviors — and their own. Sleep problems in both children and adults are under-diagnosed, even though they can have a major impact on daytime activity and health. Better sleep habits, and medical attention for issues such as snoring, daytime sleepiness, and breathing interruptions known as apnea, could help people of all ages function better during the day.
Chervin and his colleagues from UMHS, the University of Pittsburgh and Stanford University designed the study to gather as much information as possible on a large number of children, to overcome the limitations of previous studies that only looked at small groups of children who had been referred to sleep specialists.
They combined three different validated survey instruments: two asking parents about their children’s behavior patterns, and one asking about snoring, sleepiness and characteristics that may indicate sleep-disordered breathing problems. The children were all over the age of 2 and under the age of 14, and parents were asked to seek their children’s help in completing the survey. Fifty-four percent of the children assessed were boys.
The sleep portion of the survey asked about frequency and severity of snoring, as well as the tendency to struggle to breathe or stop breathing temporarily during the night, to breathe through the mouth during the day, to wake up feeling unrefreshed, or to have a hard time waking up. All these can mean a child has sleep-disordered breathing, which can affect the quality of their sleep.
Scores for snoring frequency and severity, and for sleepiness and sleep-disordered breathing, were tallied for each child, to allow each tendency to be considered on its own. And, children were designated either habitual, or non-habitual, snorers.
The behavior portion of the survey asked about attention to tasks and schoolwork, distraction, forgetfulness, fidgeting, inappropriate action and excessive talking, as well as other symptoms of attention-deficit hyperactivity disorder. The children were assigned scores based on the total number of attributes their parent said applied to them, and how often.
Sixteen percent of the children were reported to snore frequently, and 13 percent scored high on the hyperactivity index. But 22 percent of habitual snorers had high hyperactivity scores, compared with only 12 percent of those whose parents said they did not snore regularly. Similar differences were found when the researchers looked at hyperactivity scores among children who scored high on measures of sleepiness, snoring severity and sleep-disordered breathing.
The contrast in behavior between children with and without some symptoms of sleep-disordered breathing changed significantly when the researchers divided the group by age and sex. Boys under 8 years old had the biggest difference: 30 percent of those who snored regularly had high hyperactivity scores, as opposed to 9 percent of those who did not snore often. In contrast, daytime sleepiness – perhaps because it can result from many causes other than sleep-disordered breathing – was associated with hyperactivity in all age and sex groups.
Because scores for daytime sleepiness and snoring were linked closely, the researchers corrected for the effect. But they still found that those children with high sleepiness scores, regardless of snoring, tended to have high hyperactivity scores, as did children with high snoring scores, regardless of sleepiness. This suggests that sleep-disordered breathing or sleepiness from other causes could each contribute, independently, to the risk of disruptive behavior.
Fortunately, sleep breathing problems, poor sleep habits and other conditions that contribute to sleepiness – and perhaps inattention and hyperactivity -- can be corrected, Chervin notes. Evaluation and treatment by sleep specialists is important for those with apnea, severe snoring, and other conditions. And parents should make sure their children get a full night’s sleep, have a consistent bedtime and wakeup time, and follow other good sleep hygiene habits.
Besides Chervin, the study’s authors are former U-M nurse Kristen Hedger Archbold, Ph.D., now at the University of Washington; U-M child psychiatrist James Dillon, M.D; U-M pediatricians Parvis Panahi, M.D. and Kenneth Pituch, M.D., and sleep specialists Ronald Dahl, M.D. of the University of Pittsburgh and Christian Guillemenault, M.D. of Stanford University. The study was funded by the National Institutes of Health and the U-M Health System.
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