Loud snoring, which occurs in nine percent of children two to three years of age, related to behavior problems.
Persistent snoring in preschoolers, which puts them at risk for worse behavior, is most common in children in poorer families and in those breastfed for short times or not at all, a prospective study showed.
After adjustment for demographic variables, frequent snoring was significantly associated with socioeconomic status and duration of breastfeeding, according to Dean W. Beebe, PhD, of the University of Cincinnati in Ohio, and colleagues.
And while race and exposure to tobacco smoke also were associated with habitual snoring in unadjusted analyses, significance was lost after adjustment for demographics, the researchers reported online ahead of print in the September Pediatrics.
Sleep-disordered breathing is recognized as contributing to cognitive and behavioral difficulties in school-age children, but less is known about the effects in younger children.
To explore this, Beebe and colleagues examined data from the ongoing Health Outcomes and Measures of the Environment Study, including 249 children in the Cincinnati area.
Their mothers were interviewed regularly beginning during pregnancy, routinely being asked about breastfeeding and their children’s sleeping habits.
The children’s exposure to tobacco smoke, which had been associated with sleep-disordered breathing in cross-sectional studies, was assessed with serum cotinine analyses.
A total of 23 percent of the children were classified as transient snorers, in that they had snoring episodes twice or more each week at either age 2 or 3, but not at both time points.
The 9 percent of children who snored regularly at both ages were classified as persistent snorers, and the remaining 68 percent were nonsnorers.
Children who snored persistently had higher mean scores for overall behavior on the Bayley Scales of Infant Development compared with nonsnorers, the researchers reported.
Moreover, scores higher than 60 — signifying that the child is at risk for worse overall behavior — were found in 35 percent of the habitual snorers compared with 12 percent of infrequent snorers and 10 percent of nonsnorers.
“Preschool behavior and emotional problems of this magnitude were once dismissed as trivial, but are now recognized as significant sources of functional impairment at the population level,” Beebe and colleagues wrote.
Because some evidence has suggested that cotinine levels can vary according to race because of differences in metabolism of nicotine, the researchers undertook a secondary analysis to test for this interaction.
While an association between high cotinine levels and snoring was found for whites in unadjusted analyses and with adjustment for demographics (OR 2.06), the interaction failed to reach statistical significance in a fully adjusted model.
These findings, in conjunction with animal studies and observational trials of sleep disruptions in young children can lead to episodes of hypoxia that “can result in elevated oxidative stress, systemic inflammation, and changes in neural and neurobehavioral functioning,” the researchers observed.
Among the reasons why socioeconomic status could influence snoring were access to healthcare and environmental exposures.
Possible factors that may be influential for breastfeeding included immunologic function and upper airway structure in the young child.
The duration of breastfeeding also was important, with none of the children breastfed for a year or longer becoming habitual snorers, while one-quarter of those who were breastfed for less than a month or never were snoring at ages 2 and 3.
Limitations of the study were parental reporting of sleep behaviors and the lack of adjustment for sleep disorders among parents.
While definitive causal conclusions can’t be drawn in this correlation study, the findings reinforces the importance of screening for persistent snoring among young children. “It is important to ask specifically about snoring, because parents’ responses to more general sleep questions may not reflect this hallmark symptom of [sleep-disordered breathing],” the researchers advised.
The implications of the study remain uncertain, pointed out Andrew Adesman, MD, of Steven and Alexandra Cohen Children’s Medical Center of New York in New Hyde Park, N.Y.
“Although this study is helpful in demonstrating that there is an association between snoring and attention/behavior problems in preschoolers, not just older children, it is unclear what, if anything, families or pediatricians should do to reduce snoring in young children,” said Adesman, who was not involved in the study.
“Removal of the tonsils and adenoids is sometimes warranted in older children who snore and have significant difficulties with attention and behavior, but this advice may not apply to younger children because behavioral issues can disappear between ages 3 and 6 as children mature,” he added.
The suitability of interventions such as adenotonsillectomy for young children who snore is currently being evaluated in a randomized trial.
By Nancy Walsh