A study in the Dec. 15 issue of the Journal of Clinical Sleep Medicine shows that being overweight or obese increases the risk for developing obstructive sleep apnea (OSA) in adolescents but not in younger children.
Results indicate that the risk of OSA among Caucasian adolescents 12 years of age and older increased 3.5 fold with each standard-deviation increase in body mass index (BMI) z-score, while the risk of OSA did not significantly increase with increasing BMI among younger children. According to the authors, the results suggest that the increase in risk among overweight and obese adolescents may result from developmental changes such as reductions in upper airway tone and changes to anatomic structures.
"These results were a little surprising to us initially, as obesity is generally considered to increase the risk of sleep apnea amongst all children," said principal investigator Mark Kohler, PhD, research fellow at the Children's Research Centre at the University of Adelaide in Australia. "Previous results have been inconsistent, however, and appear to be confounded by using mixed ethnic populations and different ages of children."
Sleep and OSA severity were assessed by overnight polysomnography in 234 Caucasian children between the ages of 2 and 18 years. All children had been referred for evaluation of snoring and possible OSA and were reported by a parent to snore at least one night per week.
Participants were classified into six age groups, and having an average of at least one obstructive apnea or hypopnea per hour of sleep was considered to be indicative of OSA. Established growth charts corrected for age and sex were used to determine BMI z-scores and classify children as overweight (BMI ≥ 85th percentile) or obese (BMI ≥ 95th percentile).