Preschoolers who snore are twice as likely as non-snorers to have asthma or nighttime cough. A study of almost 1,000 Australian children aged 2–5 used parent-administered questionnaires to identify kids who snored four or more times week. Of the more than 100 subjects who did (and there were equal numbers of boys and girls), 42% turned out to have asthma and 62% had nighttime cough. In non-snorers, however, the two conditions were about half as prevalent at 26% and 30%. Led by Lucy Lu of the University of Sydney’s Department of Medicine, the study found a link between sawing logs and wheezing asthmatically but did not uncover the precise causal connection. Faced with a classic chicken-egg conundrum, co-investigator Dr. Colin Sullivan notes that “asthma increases the drive to breathe, and increased breathing efforts are known to induce snoring. “On the other hand”, he adds, “it’s possible that snoring causes asthma by allowing allergen-laden mucus from the upper airway to enter the airways of the lungs.”

The findings also suggest that snoring as much as asthma is the culprit behind nighttime cough. Because snoring, asthma and nocturnal cough may share a common cause, the researchers believe that treating any one of these conditions may reduce the severity of the other two.