PURPOSE OF THE STUDY.
To examine the seasonal effect on the incidence and severity of obstructive sleep apnea (OSA) in children. Pediatric obstructive sleep apnea is primarily due to adenotonsillar hypertrophy. Allergy and viral respiratory infections may contribute to OSA by promoting adenotonsillar growth.
Two hundred fifty-seven Australian children aged 3 to 12 years were referred for assessment of suspected OSA. All underwent overnight polysomnography (PSG).
Clinical analysis of the PSG data were scored according to standard criteria. The obstructive apnea hypopnea index (OAHI) was defined as the total number of obstructive apneas, mixed apneas, and obstructive hypopneas per hour of total sleep time. Children were divided into 3 groups by OSA severity: primary snoring (OAHI <1), mild OSA (OAHI 1–5), and moderate/severe OSA (OAHI >5). Data from each subject was grouped into the season in which it was obtained; summer: December to February; autumn: March to May; winter: June to August; spring: September to November.
Although the summer season had the fewest number of PSG performed because the unit was closed for the summer holidays, there was not a statistical difference in the average number of PSGs performed. OAHI values were significantly higher during winter (5.1 ± 0.8 events per hour) and spring (4.6 ± 0.9 events per hour) compared with autumn (2.4 ± 0.8 events per hour; P < .01 and P < .05, respectively) and summer (2.0 ± 0.5 events per hour; P < .05 for both). A significantly higher portion of children were categorized with moderate/severe OSA during winter compared with autumn (P < .05).
The authors point out that seasonal variation may play a role in OSA severity. They noted that OAHI values were higher when PSG was performed during winter and spring season compared with values obtained during autumn and summer. The severity of OSA may be affected by the season in which PSG is performed. For those patients with borderline results when PSG was obtained during spring of autumn, their OSA symptoms may be more severe if PSG was performed during the winter months. The authors speculate that viral illnesses, which are more common during the winter season, contribute to adenotonsillar hypertrophy and would lead to more severe symptoms of OSA.
This study reminds clinicians who interpret PSG that children may be more symptomatic with OSA during the winter and spring season. Consideration of repeating tests performed during summer and fall seasons may be helpful for children who have borderline results.
- Copyright © 2013 by the American Academy of Pediatrics