Researchers have found that the prevalence of mild sleep-disordered breathing (SDB) in young children may fluctuate seasonally. The findings were presented at SLEEP 2010, the 24th annual meeting of the Associated Professional Sleep Societies LLC in San Antonio.
The study shows that in summer and fall the prevalence of mild SDB in elementary-school children increased steadily from June (21.6%) through September (37.2%) and then decreased from September through November (6.3%). Controlling for potential confounders such as age, body mass index, gender, and race showed that the odds of mild SDB in every month was significantly lower than in September.
"What surprised us most was the dramatic impact that season had on the prevalence of SDB," said Edward Bixler, PhD, professor and vice chair for research in the department of psychiatry at Penn State University and lead study author. "The results are significant because they underscore the importance of evaluating a child's sensitivity to seasonal allergies when diagnosing and treating a child for SDB."
The study involved a random sample of 687 children in grades K-5. Their parents completed a brief questionnaire, and each child was evaluated between June and November during an overnight sleep study in the sleep laboratory. Mild SDB was defined as having an apnea-hypopnea index (AHI) of one to five breathing pauses per hour of sleep.
In a June 2009 study published in the journal SLEEP, Bixler's team reported that nasal problems such as chronic sinusitis and rhinitis are significant risk factors for mild SDB in children. However, the extent to which allergies may promote a seasonal variation in SDB still needs to be determined.