Public Release: 

Study links preschool snoring, asthma, and nighttime cough

Snoring children twice as likely as nonsnorers to have asthma, cough

American College of Chest Physicians

(NORTHBROOK, IL, August 12, 2003) - Preschool-age children who regularly snore have a higher prevalence of asthma and nighttime cough than children who do not snore, says a study published in the August issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians (ACCP). The study found that preschool children who snored were twice as likely as nonsnorers to have either asthma or nighttime cough, and that children who snored were more likely than nonsnorers to have coexisting asthma and nighttime cough.

"Physicians often use nighttime cough as a guide in diagnosing asthma in young children, and proceed to treat the asthma hoping to eliminate the cough," said lead author Lucy R. Lu, MB, MPH, Department of Medicine, University of Sydney, Australia. "Our study shows nighttime cough may be caused by snoring, rather than asthma. In these cases, treating the snoring would be more effective in reducing cough."

Researchers from the University of Sydney and The Children's Hospital at Westmead, investigated the prevalence of snoring and the association between snoring, asthma, nighttime cough, and nasal obstruction (hay fever) in preschool children. Using a parent-administered questionnaire, researchers gathered information from 974 children (516 boys and 458 girls) ages 2 through 5. In the children studied, 42.2 percent of children who snored also had asthma, compared to 26.4 percent of children who did not snore. In addition, 61.8 percent of children who snored reported nighttime cough, as compared to 30.5 percent of children who did not snore. A cross-analysis indicated 86.1 percent of children with asthma who snored also experienced nighttime cough, as compared to 52.6 percent of children with asthma who did not snore, 44.1 percent of children without asthma who snored, and 22.6 percent of children reporting no asthma or snoring. Although nasal obstruction of any kind is known to cause snoring, the prevalence of asthma in children without hay fever was significantly higher in children who snored than in children who did not snore.

"Although there is a strong correlation between asthma and snoring, the causal link between the two conditions is unclear. Asthma does increase the drive to breathe and increased breathing efforts are known to induce snoring. However, it is possible that snoring may act as a trigger for asthma by allowing allergen-laden mucus from the upper airway to enter the lung airways," said co-author Colin E. Sullivan, BSc, MB, BS, PhD, Professor of Medicine, University of Sydney. "Snoring's potential to produce adverse outcomes in behavior, learning, and possibly asthma management will make its identification and evaluation important aspects of any medical consultation in childhood."

Overall survey results indicated 10.5 percent of children snored four or more times a week, and 28 percent suffered from asthma. There was no difference in the prevalence of snoring between genders and no association with age. In addition, the prevalence of obesity in children who snored was slightly higher than in those who did not snore.

"We are constantly building the base of knowledge on chronic medical conditions in children. Understanding the interdependence of these chronic conditions and their link to nighttime cough is essential for effective medical treatment and disease management," said Udaya B. S. Prakash, MD, FCCP, President of the American College of Chest Physicians.

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CHEST is a peer-reviewed journal published by the ACCP. It is available on-line each month at www.chestjournal.org. ACCP represents more than 15,000 members who provide clinical, respiratory, and cardiothoracic patient care in the United States and throughout the world. ACCP's mission is to promote the prevention and treatment of diseases of the chest through leadership, education, research, and communication.

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