Obstructive sleep apnea, excessive daytime sleepiness, and morning plasma TNF-α levels in Greek children.

ABSTRACT

BACKGROUND: Obstructive sleep apnea (OSA) has been associated with increased frequency of excessive daytime sleepiness (EDS). Increased plasma TNF-α levels may mediate this association in adults, but conflicting results have been reported in children. We hypothesized that (i) the higher the OSA severity in childhood, the higher the frequency of EDS and morning plasma TNF-α levels; and (ii) high TNF-α levels predict presence of EDS. METHODS: Children without and with snoring underwent polysomnography. EDS was determined by parental response to specific questions, and plasma TNF-α levels were measured. RESULTS: Children with moderate-to-severe OSA (n = 24; 5.7 ± 2 years; apnea-hypopnea index [AHI] 11.5 ± 5.1/h), but not participants with mild OSA (n = 22; 6 ± 2.5 years; AHI 2.1 ± 1/h) were at significantly higher risk for EDS than controls (n = 22; 6.8 ± 2.1 years; AHI 0.5 ± 0.3/h) (OR [95% CI] adjusted for age, gender, and obesity 9.2 [1.7-50.2] and 3.8 [0.7-21.8], respectively). The 3 groups did not differ regarding TNF-α concentration (0.63 ± 0.2 vs 0.65 ± 0.18 vs 0.63 ± 0.17 pg/mL; P > 0.05). TNF-α levels were associated significantly with body mass index z-score (P < 0.05) and not with polysomnography indices (P > 0.05). Subjects with high TNF-α levels (> 0.57 pg/mL) were not at higher risk for EDS than participants with low levels (OR [95% CI] adjusted for age, gender, and obesity 1.7 [0.5-5.7]). CONCLUSIONS: Increasing severity of OSA is associated with increasing frequency of EDS, but not with elevated plasma TNF-α concentration. High TNF-α levels cannot be used as predictor for the presence of EDS in children with sleep apnea.