Plasma C-reactive protein in nonobese children with obstructive sleep apnea before and after adenotonsillectomy

Study Objective: Sleep-disordered breathing (SDB) is a prevalent condition in children and is associated with increased cardiovascular morbidity. Circulating levels of C-reactive protein (CRP), a proinflammatory protein, are associated with increased risk for atherosclerosis. Plasma CRP levels in snoring children have yielded conflicting results, such that it remains unclear whether OSA is mechanistically involved in such elevations of CRP. Methods: Consecutive nonobese children with polysomnographically demonstrated obstructive sleep apnea underwent blood draws in the morning after their corresponding sleep studies on 2 occasions, namely at diagnosis of obstructive sleep apnea and 10 to 14 weeks after adenotonsillectomy. High-sensitivity CRP serum concentrations were determined within 2 to 3 hours after collection, using a particle-enhanced turbidimetric immunoassay technique. Results: Twenty children with obstructive sleep apnea (mean age 7.3 ± 1.9 years; 55% boys; relative body mass index: 88% ± 12.0%) with a mean apnea-hypopnea index at diagnosis of 15.6 ± 2.9 events per hour of total sleep time and nadir SaO₂ of 82.3% ± 2.5% were included. Mean initial CRP levels at obstructive sleep apnea diagnosis were 0.67 ± 0.21 mg/dL and decreased to 0.23 ± 0.07 mg/dL after adenotonsillectomy (p < .05), along with significant decreases in measured apnea-hypopnea index (2.2 ± 0.8 events/h of total sleep time; p < .01) and improved oxygenation (mean nadir SaO₂ values: 88.6% ± 1.9%; p < .01). Conclusions: Obstructive sleep apnea is frequently associated with increases in CRP levels that are reversible upon treatment. Thus, obstructive sleep apnea induces a systemic inflammatory response in children, which, if left untreated, may potentially lead to cardiovascular morbidity.