RT Journal Article SR Electronic T1 Seasonal variability in paediatric obstructive sleep apnoea JF Archives of Disease in Childhood JO Arch Dis Child FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP 208 OP 210 DO 10.1136/archdischild-2012-302599 VO 98 IS 3 A1 Lisa M Walter A1 Lauren C Nisbet A1 Gillian M Nixon A1 Margot J Davey A1 Vicki Anderson A1 John Trinder A1 Adrian M Walker A1 Rosemary S C Horne YR 2013 UL http://adc.bmj.com/content/98/3/208.abstract AB Background Allergy and respiratory viral infection may contribute to the pathogenesis of sleep disordered breathing (SDB) through promoting adenotonsillar growth. We investigated the seasonal variation of SDB in children by analysing the change in the obstructive apnoea hypopnoea index (OAHI) throughout the year. Participants 257 3–12-year-old children referred for assessment of SDB underwent overnight polysomnography (PSG). Results Mean seasonal OAHI was significantly higher in winter (5.1±0.8 events/h) and spring (4.6±0.9 events/h) compared with autumn (2.4±0.8 events/h; p<0.01 and p<0.05, respectively) and summer (2.0±0.5 events/h; p<0.05 for both). There were no differences in OAHI between summer and the other seasons or between winter and spring. Conclusions We identified more severe obstructive sleep apnoea in clinically referred children during winter and spring and suggest that inflammation from respiratory viruses may contribute to adenotonsillar hypertrophy, worsening airway obstruction. Clinicians should take season into account when interpreting PSG results.