BACKGROUND: Obstructive Sleep Apnea Syndrome (OSAS) is associated with inflammation, but obesity may be a confounding factor. Thus, the aim of this study was to explore differences in serum levels of inflammation markers between obese individuals with or without OSAS.METHODS: Healthy individuals (n = 61) from an outpatient obesity clinic were examined by polysomnography and blood analysis, for measurement of TNF-alpha, IL-6, CRP, and fibrinogen levels. According to Apnea-Hypopnea Index (AHI), participants were divided into two BMI-matched groups: controls (AHI < 15/h, n = 23) and OSAS patients (AHI > or = 15/h, n = 38).RESULTS: OSAS patients had significantly higher TNF-alpha levels (P < .001) while no other difference in the examined inflammation markers was recorded between groups. Overall, TNF-alpha levels were correlated with neck circumference (P < .001), AHI (P = .002), and Oxygen Desaturation Index (P = .002).CONCLUSIONS: Obese OSAS patients have elevated TNF-alpha levels compared to BMI-matched controls, suggesting a role of OSAS in promoting inflammation, possibly mediated by TNF-a.