Oxidative stress and inflammatory markers in the exhaled breath condensate of children with OSA.

INTRODUCTION

Obstructive sleep apnea (OSA) in children has been associated with systemic inflammation and oxidative stress. Limited evidence indicates that pediatric OSA is associated with oxidative stress and inflammation in the airway.

OBJECTIVE

The objective of this study is to assess the hypothesis that levels of oxidative stress and inflammatory markers in the exhaled breath condensate (EBC) of children with OSA are higher than those of control subjects.

METHODS

Participants were children with OSA and control subjects who underwent overnight polysomnography. Morning levels of hydrogen peroxide (H(2)O(2)) and sum of nitrite and nitrate (NO(x)) in EBC of participants were measured.

RESULTS

Twelve subjects with moderate-to-severe OSA (mean age ± standard deviation: 6.3 ± 1.7 years; apnea-hypopnea index--AHI, 13.6 ± 10.1 episodes/h), 22 subjects with mild OSA (6.7 ± 2.1 years; AHI, 2.8 ± 1 episodes/h) and 16 control participants (7.7 ± 2.4 years; AHI, 0.6 ± 0.3 episodes/h) were recruited. Children with moderate-to severe OSA had higher log-transformed H(2)O(2) concentrations in EBC compared to subjects with mild OSA, or to control participants: 0.4 ± 1.1 versus -0.9 ± 1.3 (p = 0.015), or versus -1.2 ± 1.2 (p = 0.003), respectively. AHI and % sleep time with oxygen saturation of hemoglobin <95% were significant predictors of log-transformed H(2)O(2) after adjustment by age and body mass index z score (p < 0.05). No significant differences were demonstrated between the three study groups in terms of EBC NO(x) levels.

CONCLUSIONS

Children with moderate-to-severe OSA have increased H(2)O(2) levels in morning EBC, an indirect index of altered redox status in the respiratory tract.