Children who snore persistently and loudly at age 2 and 3 years are more likely to have problem behaviors at age 3 years, compared with children who don’t snore or who only snore transiently.
Those findings come from a prospective analysis of 249 mother-child pairs who were part of the Cincinnati-based Health Outcomes and Measures of the Environment (HOME) Study, which enrolled the women at or before 19 weeks’ gestation. The results highlight the importance of routine screening for snoring in particular, because parents’ responses to more general sleep questions may not reflect this hallmark symptom of sleep-disordered breathing (SDB), said Dean W. Beebe, Ph.D., of Cincinnati Children’s Hospital Medical Center, and his associates (Pediatrics 2012 Aug. 13 [doi:10.1542/peds.2012-0045]).
The findings of this study, believed to be the first to examine the relationship between the persistence of snoring and behavioral functioning in preschool-aged children, also suggest that screening is particularly important for children from lower socioeconomic backgrounds who are at higher risk for persistent SDB and its associated morbidity. It is also important to document whether snoring persists, the investigators said.
Snoring was assessed when the children were aged 2 and 3 years with the validated Child Sleep Habits Questionnaire, which asked parents to report how often their child "snored loudly" during the previous week. Of the 249 children, 170 (68%) were "nonsnorers" whose parents reported that they "rarely" snored loudly over the previous week. Another 57 children (23%) were "transient snorers," who snored loudly two or more times per week at either age 2 or 3 years but not both, and 22 (9%) were "persistent snorers," who snored two or more times per week at ages 2 and 3 years.
Parents completed the validated preschool form of the Behavior Assessment System for Children, and a trained research associate administered the Bayley Scales of Infant Development. Prenatal exposure to tobacco was assessed through maternal serum cotinine measures during pregnancy, and childhood tobacco exposure was assessed through collected serum. The mothers were surveyed about breast feeding, and the children were examined at annual visits.
The three groups did not differ significantly with regard to gender, birth weight, or gestational age. In the unadjusted analysis, the persistent snorers tended toward a higher body mass index z score than did the transient snorers or the nonsnorers at both the 2-year and 3-year assessments. Persistent snorers had significantly higher prenatal and childhood cotinine levels than did either of the other two groups at both time points.
Persistent snorers were significantly more likely to be African American (55% versus 13.5% of the nonsnorers), and to have lower parental education and annual family income ($49,000 vs. $84,000). None of the children fed breast milk for more than 12 months developed persistent snoring, but nearly one-quarter of those who were never fed breast milk, or who received breast milk for less than 1 month, did so.
Persistent snorers had significantly worse overall behavioral functioning than did the nonsnorers and transient snorers. Overall Behavioral Symptoms Index (BSI) scores were 49.2 for the nonsnorers, 50.9 for the transient snorers, and 57.6 for the persistent snorers, with a P value of less than .001 for the persistent snorers versus the other two groups. The difference was particularly significant with regard to hyperactivity, depression, and attention.
"At risk" or worse overall behaviors, defined as a BSI index score of 60 or greater, were reported in 35% of persistent snorers, compared with 10% of nonsnorers and 12% of transient snorers. "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," Dr. Beebe and his associates noted.
These results are consistent with reports on older children, and remained significant after the researchers controlled for child gender, race, and socioeconomic status.
Definitive causal conclusions can’t be drawn from this study. However, the findings are consistent with previous data suggesting that SDB-mediated sleep disruption and intermittent hypoxia can result in elevated oxidative stress, systemic inflammation, and changes in neural and neurobehavioral functioning. An ongoing randomized trial is currently examining the effect of surgical treatment of SDB on cognitive and behavioral functioning (Sleep 2011;34:1509-17).
A simple screening tool called BEARS (Bedtime Issues, Excessive Daytime Sleepiness, Night Awakenings, Regularity and Duration of Sleep, Snoring) has shown utility for identifying sleep problems in the primary care setting (Sleep Med. 2005;6:63-9).
None of the authors have any conflicts of interest to declare.