Association between seasonal factors and severity of obstructive sleep apnea-hypopnea syndrome in children

Background: Limited data are available on the relationship between seasonal factors and obstructive sleep apnea-hypopnea syndrome (OSAHS) in China. The aim of this study was to investigate the effects of seasonal factors on the severity of OSAHS in children. Methods Children presenting with snoring and/or mouth breathing, suspected of having OSAHS, and admitted to the Department of Respiratory Medicine of the Children's Hospital of Soochow University from December 2016 to February 2022 were enrolled in this study. The severity of OSAHS was determined by full-night polysomnography (PSG) in the sleep laboratory. The correlation between seasonal factors and PSG monitoring results was analyzed. Results Of the 589 included patients, 301 cases (51.1%) were diagnosed with OSAHS. Among them, 77 cases (25.6%) were detected in spring, 74 cases (24.6%) were detected in summer, 59 cases (19.6%) were detected in autumn, and 91 cases (30.2%) were detected in winter. There were 238 cases (79.1%) of tonsillitis hypertrophy, 276 cases (91.7%) of adenoid hypertrophy, 215 cases (71.4%) of rhinitis/sinusitis, and 36 cases (12.0%) of asthma. The proportion of rhinitis/sinusitis and tonsillar hypertrophy in spring was higher than that in summer ( P  = 0.015 and 0.036, respectively), and the proportion of adenoid hypertrophy in winter was higher than that in summer ( P  = 0.024). The diagnostic rate of severe OSAHS in winter was higher than that in summer ( χ 2  = 7.053, P  = 0.008). The respiratory arousal index in winter was higher than that in summer ( H = -39.297, P  = 0.018), and the spontaneous arousal index in spring was higher than that in autumn ( H  = 44.059, P  = 0.020). It was found that the rapid eye movement (REM)-apnea index (AI) in spring and winter was higher than that in summer ( H  = 52.292, -52.554; all P  < 0.05). The comparison of PSG results of children with OSAHS under the age of 7 years in different seasons showed that the respiratory arousal index in winter was higher than that in summer ( H = -35.570, P  = 0.008). The REM-AI in winter and spring was higher than that in summer and autumn, respectively ( H = -33.929 and − 38.632; H  = 30.665 and 35.368, all P  < 0.05). Conclusion Severe OSAHS is more common in winter. Respiratory events are increased in spring and winter, mainly in preschool children. Seasonal factors may have a certain impact on OSAHS.