TNF and obstructive sleep apnea syndrome: TNF-α gene expression was increased in OSA patients as compared with that in PS subjects (3.08 ± 4.25 vs. 1.32 ± 1.18 fold change, regression coefficient 1.913, 95%CI 0.037 to 3.456, adjusted p = 0.016, Figure 1a), and positively correlated with AHI (r = 0.388, p = 0.003, Figure 1b).