Mar 5, 2012 5:02 AM
March 5, 2012 -- The more young children snore, breathe through their mouths, or stop breathing while asleep for a few seconds at a time, the more likely they are to develop behavioral problems, a new study shows.
Previous research had suggested a link between these "sleep-disordered breathing" symptoms and such problems as hyperactivity, but the authors of the new study say theirs is by far the largest and most comprehensive of its kind.
The researchers followed more than 11,000 children in an ongoing study in southwest England. The study enrolled pregnant women who were due to deliver between April 1991 and December 1992.
For the latest findings, researchers asked parents to fill out questionnaires about their children's snoring, mouth breathing, and apnea, which refers to abnormal pauses in breathing while asleep. The questionnaires were completed when the children were 6, 18, 30, 42, 57, and 69 months of age. When their children were 4 and 7 years old, the parents were asked to complete questionnaires about their children's behavior.
About 45% of the children breathed just fine while asleep, according to their parents. Of the rest, the "worst case" children had elevated levels of all three breathing symptoms at 30 months of age, says researcher Karen Bonuck, PhD, a professor of family and social medicine and of obstetrics and gynecology and women's health at Albert Einstein College of Medicine in New York.
After accounting for 15 other factors linked to behavioral problems, such as low birth weight and mom's education, Bonuck's team found that children with sleep-disordered breathing were 40% to 100% more likely to experience behavioral problems at age 7 than children without breathing problems.
The worse their breathing symptoms, the greater their risk of such problems as hyperactivity, behavioral problems including aggressiveness and rule-breaking, anxiety and depression, and difficulty getting along with peers.
Despite the research linking snoring to behavioral problems, more than half the parents surveyed at one hospital's primary care clinic said they thought it was a sign of healthy sleep in children, according to a report last year in the Journal of Developmental and Behavioral Pediatrics.
"The take away is that parents need to pay closer attention to their child's breathing while they're sleeping," Bonuck says. "If they suspect their child is showing symptoms of sleep-disordered breathing, they should ask their pediatrician or family physician if their child needs to be evaluated by an ear, nose, and throat physician or a sleep specialist."
Scientists have many theories about why sleep-disordered breathing increases children's risk of behavioral problems, she says. Infancy and young childhood are key periods of brain development, and breathing problems might decrease oxygen in the brain.
Plus, the authors note, breathing problems could interrupt the restorative processes of sleep and disrupt the balance of various cellular and chemical systems.
Could the decades-long decline in tonsillectomies be partly responsible for the increased diagnoses of behavioral problems? "This is certainly a possibility," says Bonuck's co-researcher Ronald Chervin, MD, professor of sleep medicine and of neurology at the University of Michigan.
Recurrent throat infections used to be the main reason children had their tonsils and adenoids removed, but now the operation, called an adenotonsillectomy, is performed nearly as frequently for suspected obstructive sleep apnea, Chervin says.
Much remains to be learned about the age at which sleep apnea needs to be investigated and treated in children and the benefits of removing the tonsils and adenoids, he says.
The National Heart, Lung, and Blood Institute is funding a study of nearly 500 children with obstructive sleep apnea and enlarged tonsils to help answer some of those questions. All of the children, ages 5 to 9, will get their tonsils and adenoids removed, but they are being assigned to get surgery either immediately or after seven months of "watchful waiting." The study is expected to be completed in June.
Bonuck and Chervin's study is posted online by the journal Pediatrics.