Less Sleep, More Behavioral Problems in Kids

Children who have relatively short nighttime sleep duration are at high risk for several externalizing behavioral problems, new research suggests.

A cohort study of almost 9000 preschool-aged children showed that those who averaged fewer than 9 hours of sleep per night were significantly more likely to show impulsivity, anger, and overactivity and to have tantrums than their peers who averaged more nightly sleep.

The children with less sleep were also 80% more likely to show aggression.

"Although the results were not surprising, there was no certainty that we would find the kind of relationship that we did between behavior and amount of sleep that these children had," co–senior investigator Ruth E. K. Stein, MD, professor of pediatrics at the Albert Einstein College of Medicine in New York City and from the Children's Hospital at Montefiore Medical Center, told Medscape Medical News.

"And the relationship we found was perhaps stronger than we might have expected," added Dr. Stein.

Although the study could not prove causality, the researchers note that the findings do suggest that sleep duration is critically important to a young person's health and well-being.

"[H]ealth care providers should be encouraged to inquire about bed and wake times when a child presents with a behavior concern," the authors write, adding that "advocating for regular sleep habits, healthy sleep hygiene, and regular bedtime routines may be helpful."

The study is published in the July/August issue of the Journal of Developmental and Behavioral Pediatrics.

Bad Behavior Not the Only Problem

Dr. Stein noted that lead author Rebecca Scharf, MD, MPH, from the University of Virginia in Charlottesville, was originally startled that so many of the people she knew both clinically and socially were commenting on sleep issues of their young children.

"She was struck by the fact that there was really no information on how much children in that age group should be sleeping. And that really motivated her to delve into this topic," said Dr. Stein.

A recent study, reported by Medscape Medical News, showed that irregular bedtimes throughout early childhood can impair cognitive development.

"Reduced or disrupted sleep, especially if it occurs at key times in development, could have important impacts on health throughout life," wrote the study authors at the time.

For the current study, data were examined for 8950 American 4-year-olds from the Early Childhood Longitudinal Study–Birth Cohort (ECLS-B; 51.3% boys; 53.8% white, 25.1% Hispanic, 13.9% black, 7.3% other).

The children's sleep duration was estimated on the basis of computer-based parental reports of weekday bed and wake times. The parent-reported Preschool and Kindergarten Behavior Scale, Second Edition (PKBS-2) was used to rate 6 externalizing behaviors.

The overall mean bedtime for all children was 8:39 pm. The mean wake time was 7:13 am.

For this analysis, the investigators assessed sleep duration of fewer than and more than 9.44 hours, which was 1 standard deviation below the mean amount.

Results showed that children who averaged fewer than 9.44 hours of sleep per night (11% of the participants) had higher adjusted odds of having all 6 of the behavioral problems examined compared with the children who had more hours of nightly sleep:

Behavior	AOR*	95% CI†	P Value
Aggression	1.81	1.36 - 2.41	< .001
Tantrums	1.46	1.16 - 1.85	= .002
Impulsivity	1.44	1.12 - 1.86	= .005
Anger	1.40	1.15 - 1.71	< .001
Annoying behaviors	1.40	0.97 - 1.87	= .072
Overactivity	1.30	1.03 - 1.65	< .025
*AOR, adjusted odds ratio †CI, confidence interval

 

The participants' sex, number of hours of television viewing, and maternal depressive symptoms were not individual risk factors for shorter sleep duration. However, boys who watched more than 2 hours of television per night and boys who had mothers with depressive symptoms had worse overall behavior scores than other subgroups.

Study limitations cited included its cross-sectional design, which means that causality could not be determined, and that the PKBS-2 "is not a regularly used scale."

Chicken or the Egg?

Dr. Stein noted that the study also did not measure all sleep that a child might have had, including napping.

"And parental reports about how much their children are sleeping are not 100% accurate. So with all of these factors, it was impressive how strong the relationship [between sleep duration and behaviors] was and that it came through so clearly," she said.

She said that going forward, clinicians should ask parents how much actual sleep their children are getting each night.

"If it's not the usual amount of sleep that's recommended, they should be exploring the reasons for that and what the families might be able to do to encourage more sleep," said Dr. Stein.

Still, she reiterated that the study does not show cause and effect.

"So we can't really say whether it's an emotional disturbance in the children that's preventing them from sleeping or if it's the sleep deficit that's causing the emotional disturbance. That's going to take some further analysis."

The study authors have disclosed no relevant financial relationships.

J Dev Behav Pediatr. 2013;34:384-391. Abstract

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Cite this: Less Sleep, More Behavioral Problems in Kids - Medscape - Jul 18, 2013.