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.