title: Seasonal variation in a clinical referral pediatric cohort at risk for obstructive sleep apnea.
abstract: OBJECTIVE
  The present study was carried to examine the hypothesis that the severity of obstructive sleep apnea (OSA) in a clinical referral population of children would manifest seasonal variability in their polysomnographic findings.
  
  
  METHODS
  The study population comprised consecutive children referred for evaluation of habitual nighttime snoring, parentally witnessed apnea during sleep, and difficult or noisy breathing during sleep. A total of 554 children were identified as eligible and underwent full-night polysomnography (PSG). Monthly fluctuation patterns in PSG measures were assessed in 2 age groups (<6 and ≥ 6 years old).
  
  
  RESULTS
  In the younger group, the lowest AHI was found in the month of August (9.5 ± 1.7/hrTST) while December emerged as the month with the lowest AHI for the older group (8.7 ± 2.3/hrTST). The highest AHI was in January (24.8 ± 7.5/hrTST) in the group ≥ 6 years old, and in March (32.7 ± 6.9/hrTST) in the younger group.
  
  
  CONCLUSIONS
  Seasonal changes are present in children with clinically symptomatic OSA and differ among younger and older children, with global trends toward improved AHI during summer, especially in younger children. Future studies should be conducted to define a "correction factor" for the month of PSG assessment that will enable accurate decision making when evaluating symptomatic children with habitual snoring.
authors.affiliation: Department of Otolaryngology, Nagoya City University, Nagoya, Japan. nakayama@med.nagoya-cu.ac.jp
authors.forename: Meiho
authors.initials: M
authors.lastname: Nakayama
authors.forename: Shigefumi
authors.initials: S
authors.lastname: Koike
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kuriyama
authors.forename: Motohiko
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Katsunori
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Shingo
authors.initials: S
authors.lastname: Murakami
authors.forename: David
authors.initials: D
authors.lastname: Gozal
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D017286:Polysomnography; D012017:Referral and Consultation; D012306:Risk; D012621:Seasons; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology / Q000503:physiopathology*