Aim: To evaluate a range of inflammatory measures in children with obstructive sleep apnoea (OSA).
Methods: In total, 44 children with polysomnographically defined OSA (30 boys; mean age: 7.3 +/- 3.7 years) and 69 control subjects (44 boys; mean age: 7.6 +/- 4 years) were recruited. Controls were screened for symptoms of OSA by questionnaire at the time of elective surgery that was unrelated to the upper airway. Blood samples were analysed for C-reactive protein, and cytokines IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, GM-CSF, IFN-gamma and TNF-alpha.
Results: The majority of the children had mild OSA (32/44). Children with OSA (respiratory disturbance index 5.3 +/- 6.5 events/h) had significantly higher IFN-gamma and IL-8 levels than controls (P < 0.001 and 0.003, respectively), although correction for age, sex and body mass index reduced these differences (IFN-gammaP = 0.002, and IL-8 P = 0.051). There were no significant correlations between inflammatory measures and body mass index, respiratory disturbance index, or other sleep, desaturation, or arousal parameters including respiratory or spontaneous arousal indices, desaturation index or severity, sleep efficiency, or apnoea/hypopnoea duration in the OSA group.
Conclusion: Children with OSA, even of mild severity, have significantly elevated IFN-gamma levels and a trend towards elevated IL-8 levels compared with asymptomatic controls, consistent with a pro-inflammatory effect of OSA. These changes seen in mild OSA may precede changes in other pro-inflammatory cytokines found in studies of adults with more severe and long-standing disease, implying a potential benefit from early disease identification and intervention.