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14-08-2011 | General practice | Article

Obstructive sleep apnea linked to oxidative stress in children’s airways


Free abstract

MedWire News: Children with obstructive sleep apnea (OSA) show evidence of oxidative stress in their airways, say Greek researchers.

Writing in the journal Sleep and Breathing, Athanasios Kaditis (Aghia Sophia Children's Hospital, Athens) and team explain that previous research indicates that "similar to asthma in childhood, pediatric OSA is related to enhanced oxidative stress and inflammation in the airway," but the evidence is limited.

To investigate further, the team studied 34 children with OSA and 12 without the condition (controls) who were aged between 4 and 14 years.

Of the children with OSA, 12 had moderate-to-severe disease, with a mean apnea-hypopnea index (AHI) of 13.6 episodes per hour, and 22 had mild disease, with a mean AHI of 2.8 episodes per hour.

Both groups of children with OSA and controls were similar in terms of age, body mass index (BMI) z score, gender distribution, and ratio of obese-to-non-obese participants.

All of the participants underwent overnight polysomnography in a sleep disorders laboratory, during which oxygen saturation of hemoglobin (SpO2) was measured.

In the morning, exhaled breath condensate (EBC) samples were collected from the children between 7.00 am and 8.00 am and assessed for levels of hydrogen peroxide (H2O2) and the sum of nitrites and nitrates (NOx).

The researchers found that children with moderate-to-severe OSA had significantly higher log-transformed H2O2 concentrations in EBC than those with mild OSA, at 0.4 versus -0.9, while those with mild OSA had significantly higher concentrations than controls (-1.2).

There were no significant differences between the groups regarding NOxlevels in EBC.

After accounting for age and body mass index, the team found that AHI and the percentage of sleep time in which oxygen saturation of hemoglobinwas less than 95% were significant predictors of log-transformed H2O2concentrations.

Kaditis and team conclude: "In the present investigation, higher H2O2 EBC levels were demonstrated in children with OSA compared to control participants. This finding is indicative of increased oxidative stress in the airway of sleep apneic children."

They add: "Pediatric OSA is not only the result of an imbalance between mechanical forces, but it is also related to systemic and airway inflammation andpossibly oxidative stress."

By Mark Cowen

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