Obstructive sleep-disordered breathing is associated with cardiovascular disease in adults, and elevated C-reactive protein (CRP) has been proposed as a link between the two disorders. We hypothesized that children with sleep-disordered breathing have higher CRP values than do control subjects. CRP was measured in 39 children (mean age +/- SD: 6.9 +/- 3.2 years) without snoring (controls) and in 102 children (6.2 +/- 2.2 years) with habitual snoring who underwent polysomnography. No significant differences were found in mean CRP values between control subjects (0.12 +/- 0.16 mg/dl; n = 39) and snorers with an apnea-hypopnea index of less than 1 episode/hour (0.15 +/- 0.26; n = 18), snorers with an index of 1 or more and less than 5 (0.15 +/- 0.26; n = 54), and snorers with an index of 5 or more (0.22 +/- 0.43; n = 30; p > 0.05). There was no correlation between CRP or log-transformed CRP values and apnea-hypopnea index, respiratory movement/arousal index, Sa(O(2)) nadir, oxygen desaturation (>/= 4%) of hemoglobin index, or percentage of sleep time with saturation less than 95% (p > 0.05). Thus, findings of higher CRP values in adults with sleep-disordered breathing and correlations of these values with polysomnography indices were not confirmed in children.