SUMMARYThe goal of this study was to characterize sleep and respiratory parameters in children with sleep-disordered breathing (SDB) as compared to children without SDB. Data are from 198 children and adolescents referred for sleep center evaluation, 128 of whom were diagnosed with SDB. In children with SDB, obesity (> 95% wgt for age) was more common than being severely underweight (< 5% wgt for age), but only the older children with SDB were heavier than age-matched normal sleepers. Children with SDB had increased EEG arousals; sleep architecture was not otherwise significantly different from the non-SDB group. African-American children with SDB had significantly greater oxygen desaturation with obstructive events compared to Caucasian and Latino children. It appears that the role of obesity as a risk factor for obstructive sleep apnea (OSA) increases in children above the age of 8-years. Additionally, African-American children with SDB may be at increased risk for hypoxemia and cardiovascular consequences of SDB.

To determine sleep effects on baro- and ventilatory responses to transient chemo- and barostimulation in African-Americans and Caucasians, 26 nonobese normotensive young subjects (13 African-Americans and 13 Caucasians) were studied awake and in non-rapid-eye movement (NREM) and rapid-eye-movement sleep during induced transient hypoxemia (N2), hypertension (phenylephrine, PE), and concomitant hypoxemia and hypertension (N2 + PE). Arterial blood pressure was recorded by plethysmographic volume clamp, minute ventilation by pneumotachograph, and arterial O2 saturation by pulse oximeter. For all subjects, chronotropic baroresponse (Deltapulse interval/Deltasystolic blood pressure, where Delta is change) increased with NREM sleep (P = 0.007). Baroresponse slope was greater in Caucasians than in African-Americans (ANOVA, P = 0.02). Hypoxemic ventilatory response (Deltaminute ventilation/Deltaarterial O2 saturation) was greater in African-Americans than in Caucasians in NREM sleep (P = 0.01), as was hypoxemic attenuation of baroresponse (N2 + PE, P = 0.03). These data suggest sleep-related differences in arterial chemo- and baroreceptor responses in normal young African-Americans and Caucasians, which may have implications concerning development of systemic hypertension.