Snoring toddlers may develop behavioural problems later: Study

By Dr. Ananya Mandal, MDMar 5 2012

A new study shows that babies and toddlers who snore, gasp for breath, or breathe with their mouth open while sleeping may be at a greater risk of behavioural problems all the way through second grade.

The researchers from New York’s Albert Einstein College of Medicine got more than 11,000 British parents fill in survey forms. Those who reported that their children snored or had other breathing abnormalities while sleeping from the age of 6 months to 7 years were 50 percent more likely than their peers who breathed normally to exhibit some sort of behavioural problem such as hyperactivity, frequent temper tantrums, or anxiety.

Children who fell into the “worst case” group, where snoring and other breathing issues started early, occurred frequently, and lasted into elementary school, were more than twice as likely to wind up with behaviour issues. Nearly 18 percent of them had some sort of behavioural problem by age 7 compared with slightly more than 8 percent of those who didn’t snore. The researchers took into account differences between the groups on characteristics including body mass index, premature birth, and whether their mothers smoked during pregnancy.

“It probably has to do with an abnormal gas exchange where the brain gets too little oxygen during sleep, which has potential effects on the prefrontal cortex,” said study author Karen Bonuck, referring to the area of the brain that governs self-control and decision-making. Breathing issues may also lead to a deficit of deep sleep, which doesn’t allow the brain to fully restore itself and repair daily damage to cells. “We are sleeping to restore our brains, and sleep-disordered breathing interferes with that process,” Bonuck explained. “For kids, these are critical periods in brain development.”

Bonuck advises parents not to be alarmed since breathing problems in toddlers is common. In the study, 55 percent of parents reported that their children exhibited disordered breathing behaviours -- and most of these children didn’t have any behavioural problems.

The study is published online March 5 and in the April print issue of Pediatrics.

Co-author Dr. Ronald Chervin added, “Until now, we really didn't have strong evidence that SDB actually preceded problematic behaviour such as hyperactivity ... But this study shows clearly that SDB symptoms do precede behavioural problems and strongly suggests that SDB symptoms are causing those problems.” About one in 10 children snore regularly and two to four percent have sleep apnea, according to the American Academy of Otolaryngology -- Health and Neck Surgery.

Heidi Connolly, division chief for pediatric sleep medicine at University of Rochester Medical Center in New York, said the study adds to a growing body of research showing that snoring, mouth breathing and sleep apnea in children should be taken seriously. “These findings echo many of the other studies that show having sleep apnea and symptoms of snoring are bad for neurodevelopmental outcomes in children,” Connolly said.

While snoring is a symptom of sleep apnea, it can have other causes, such as nasal allergies. Other studies suggest that even snoring alone, without apnea, can cause kids to do worse developmentally, she added. “We need to think of that in primary care settings, and screen children for snoring,” she said. “Kids who snore need to be evaluated and treated promptly, as you would any other medical condition.”

Snoring occurs when the palate and the base of the tongue vibrate against each other. In sleep apnea, the airway is blocked. When kids try to breathe, negative pressure squeezes the airway shut, Connolly explained. That causes kids to wake up partially to take a breath. Obesity is a major risk factor for sleep apnea in children, but normal-weight kids can get it, too.

“If your child is snoring on a nightly basis, not just when they are exposed to tobacco smoke or they have a cold or they just hung out with the neighbours' cat that they're allergic to, those children need to be evaluated for sleep apnea,” Connolly said.

Parents should, though, discuss snoring or other breathing abnormalities during sleep with their child’s doctor. The American Academy of Pediatrics recommends that doctors screen for sleep apnea in children and refer them on for exams with ear, nose and throat specialists if they suspect any problems. Treatments can include removing the tonsils and adenoids; topical nasal steroids or other anti-inflammatory medications; weight loss; and continuous positive airway pressure (CPAP) devices.