Figure 1.

Scattergrams of individual tumor necrosis factor (TNF)-α morning plasma levels plotted against corresponding obstructive apnea-hypopnea index (OAHI), nadir SaO₂, and sleep pressure score (SPS) in 270 habitually snoring children and 28 nonsnoring control subjects. Linear regression lines are shown and were highly signicant for OAHI (r²: 0.24; P < 0.001) and SPS (r²: 0.52; P < 0.000001) but not with nadir SaO₂ (r²: 0.05; p > 0.05). The vertical lines show OAHI = 5 and SPS = 0.25 as cutoffs for disease severity. The right bottom panel shows log TNF-α plotted against log SPS, with the vertical line representing SPS = 0.25 whereas the curvilinear line represents the sigmoidal t function (r²: 0.64; P < 0.00000001). Please note the marked take off of TNF-α morning plasma concentrations once SPS exceeds the 0.25 cutoff value (7).