Obstructive Sleep Apnea, Excessive Daytime Sleepiness, and Morning Plasma TNF-α Levels in Greek Children

Background: Obstructive sleep apnea (OSA) has been associated with increased frequency of excessive daytime sleepiness (EDS). Increased plasma TNF-alpha 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-alpha levels; and (ii) high TNF-alpha 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-alpha 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-alpha concentration (0.63 +/- 0.2 vs 0.65 +/- 0.18 vs 0.63 +/- 0.17 pg/mL; P > 0.05). TNF-alpha 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-alpha 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-alpha concentration. High TNF-a levels cannot be used as predictor for the presence of EDS in children with sleep apnea.