Children who snore, or have other breathing difficulties at night, could grow up to have behavioural problems such hyperactivity and aggressiveness, according to a study.
The six year long research project followed over 11,000 children and found that those who had sleep-disordered breathing (SDB) such as snoring and sleep apnoea – abnormally long pauses during sleep - showed signs of behavioural issues as young as three years old.
About one in 10 children snore regularly and two to four per cent have sleep apnoea, according the American Academy of Otolaryngology–Health and Neck Surgery. The sleep problems could be caused by enlarged tonsils or adenoids.
"Until now, we really didn't have strong evidence that SDB actually preceded problematic behaviour such as hyperactivity," said Ronald D. Chervin, a co-author of the study and professor of sleep medicine and of neurology at the University of Michigan.
“This study shows clearly that SDB symptoms do precede behavioural problems and strongly suggests that SDB symptoms are causing those problems."
The new study analyzed the combined effects of snoring, apnoea and mouth-breathing patterns on the behaviour of children enrolled in the Avon Longitudinal Study of Parents and Children, a project run by University of Bristol.
Parents were asked to fill out questionnaires about their children's SDB symptoms at various intervals, from six to 69 months of age.
When their child was four and seven years old, parents filled out a Strengths and Difficulties Questionnaire (SDQ) to assess general behaviour. The SDQ has scales for assessing a child's inattention/hyperactivity, emotional symptoms such as anxiety and depression, peer problems, conduct problems like aggressiveness and rule-breaking, and prosocial behaviour such as sharing and helpfulness.
"We found that children with sleep-disordered breathing were from 40 to 100 per cent more likely to develop neurobehavioral problems by age seven, compared with children without breathing problems," said study leader Karen Bonuck, Ph.D., professor of family and social medicine and of obstetrics & gynecology and women's health at Albert Einstein College of Medicine of Yeshiva University, New York.
"The biggest increase was in hyperactivity, but we saw significant increases across all five behavioural measures."
Children with the most serious behavioural problems were those with SDB symptoms that persisted throughout the evaluation period and became most severe at 30 months.
Researchers found that a child’s sleep-breathing problems could bring on behavioural issues for many different reasons. A decrease in oxygen levels and increase in carbon dioxide in the brain, the interruption of the natural sleep restorative process and an imbalance in various cellular and chemical systems within the body were all mentioned as causes.
"This is the strongest evidence to date that snoring, mouth breathing, and apnoea can have serious behavioural and social-emotional consequences for children," commented Dr Bonuck.
"Parents and paediatricians alike should be paying closer attention to sleep-disordered breathing in young children, perhaps as early as the first year of life.”