To investigate the relationship between obstructive sleep apnea syndrome (OSAS) and exhaled nitric oxide (eNO) in overweight children and adolescents without asthma or atopy and to assess whether obesity per se is associated with increased airway inflammation.
Consecutive overweight subjects without symptoms of asthma or allergy were recruited at a pediatric obesity clinic. A normal-weight control group without OSAS and asthma or allergy was also recruited. All subjects underwent polysomnography and two measurements of eNO (afternoon and morning after polysomnography).
Controlling for age, the mean (± SD) afternoon eNO concentration was significantly higher in the snoring group (14.1 ± 1.1 parts per billion [ppb]) compared with the normal-weight group (10.1 ± 0.8 ppb; p = 0.03) and with the overweight group with normal polysomnography findings (8.9 ± 0.8 ppb; p = 0.007). The afternoon eNO concentration was also different between the OSAS group (11.9 ± 1.0 ppb) and the overweight group with normal polysomnography findings (p = 0.03). Morning eNO values were higher in the OSAS group (12.3 ± 1.1 ppb) than in the normal weight group (9.9 ± 0.8 ppb; p = 0.047) and in the overweight control group (9.7 ± 0.7 ppb; p = 0.02). BMI z score was not significantly correlated with afternoon eNO concentration or with morning eNO concentration.
This study illustrates that both habitual snoring and OSAS are associated with increased airway inflammation in overweight children as assessed by higher eNO levels. Furthermore, it was demonstrated that childhood obesity in the absence of sleep-disordered breathing is not associated with increased airway inflammation.