0779 Asthma Control and Inflammation in Asthmatic Children with Obstructive Sleep Apnea

Abstract

Introduction: Asthma affects 9% of children in the U. S. and disproportionally affects minority children of lower socioeconomic status living in urban areas, reflected in increased rates of hospitalization and mortality among those children. Evidence supports an association between obstructive sleep apnea (OSA) and poor asthma control, but the mechanisms of this association are unclear. This study aimed to determine whether, in children with asthma, increasing OSA severity was associated with increased systemic and upper airway inflammatory markers; and whether increasing inflammation was associated with decreasing asthma control. Methods: Non-obese children with persistent asthma (n=27) aged 4-12 years were recruited. Seven had no OSA and 20 had OSA measured by an apnea-hypopnea index (AHI) of 1.5 or greater, and were scheduled for adenotonsillectomy. Overnight, in-lab polysomnography was performed on all children. Blood was collected from all participants, and one tonsil was harvested during adenotonsillectomy from children undergoing surgery. Eleven cytokines were measured in serum and tonsillar supernatants. Exhaled nitric oxide (FeNO) was measured in children 7 and older. Asthma control was measured with the Child Asthma Control Test (cACT). Results: Twelve participants (44.4%) were male, and 92.6% were African American. Age averaged 7.9 years, and mean BMI z-score was 0.33. Asthma was poorly controlled in 48.1% of the sample. Higher AHI in REM sleep (p<0.05) and lower nadir SpO2 (p=0.008) were significantly correlated with higher tonsillar TNF-α. As asthma control worsened, serum cytokines IL-10 and IL-13, and tonsil TNF-α increased (all p<0.05). No polysomnographic measures of OSA severity nor FeNO were associated with cACT scores. Conclusion: OSA severity was associated with airway inflammation, but was not associated with asthma control. Asthma control worsened as cytokine markers of airway and systemic inflammation increased. The reciprocal relationship between OSA and asthma control may be due to unmeasured factors common to both diseases.