Purpose: To evaluate the association of recently diagnosed obstructive sleep apnea (OSA) with TNF-α and IL-6 and to measure the effect of short-term continuous positive airway pressure (CPAP) therapy on these markers.
Methods: A prospective, open-label, controlled trial was conducted among patients referred for diagnostic polysomnography (PSG). After PSG, patients were divided into 3 groups: OSA intervention group (N = 21), OSA control untreated group (N = 19), and non-OSA control group (N = 24). IL-6 and TNF-α levels were measured at baseline and 1 month after intervention. Repeated measures (RM) ANOVA and ANCOVA were used to compare the three groups regarding changes in TNF-α and IL-6 levels by analyzing between-subject and within-subject effects as a function of time and adjusting for significant covariates.
Results: At baseline, IL-6 (p = 0.05) and TNF-α (p = 0.04) were significantly higher in the OSA patients than in the non-OSA controls. There was no effect of time either on the TNF-α (p = 0.069) or IL-6 (p = 0.717) after 1 month of CPAP. No interaction effect between group and time was found for either TNF-α (p = 0.240) or IL-6 (p = 0.552) after 1 month of CPAP. There was neither a group effect nor an interaction effect between group and time for either IL-6 or TNF α after adjusting for age, BMI, neck circumference, and AHI.
Conclusion: This study showed increases in proinflammatory state as illustrated by plasma TNF-α and IL-6 levels among recently diagnosed OSA patients, but there were no changes in these inflammatory markers following 1-month CPAP therapy.
Keywords: IL-6; Inflammation; Markers; Obstructive sleep apnea; TNF-α.