C reactive protein and obstructive sleep apnea in obese patients

INTRODUCTION The activation of inflammatory mechanisms in obstructive sleep apnea (OSAS) as a possible explanation of the increased cardiovascular risk has been repeatedly suggested by the detection of increased levels of biomarkers such as TNF alpha, selectins, adhesion proteins, interleukins, and particularly the C-reactive protein (CRP). AIMS AND METHODS We investigated the relationship among CRP, clinical and laboratory data and nocturnal cardiorespiratory monitoring parameters in a group of obese patients (42F, 44M mean BMI 43,9) submitted for suspected, never treated OSA, aged from 20 to 68 years (mean 44,3). RESULTS Mild, moderate and severe OSA syndrome was diagnosed in 20, 24 and 46% of patients. Greater values of AHI, ODI, creatinine, hemoglobin and lower HDL cholesterol levels were detected in men compared with women, with similar age and BMI. CRP was greater in women(9.86+5.6 vs 6.66+3.6, p 0.016). Its levels were significantly associated with larger values of BMI (r 0.34, p 0.011) and lower of creatinine (r -0.26, p 0.05). Only the correlation with BMI was independent from other covariates. No significant correlation was detected between CRP and age or OSAS parameters. Only among women RCP positively correlated with serum glucose (r 0.49 p 0.023), insulin (r 0.43, p 0.048), and C peptide (r 0.59, p 0.004). Only among men, a small significant increase of CRP was found in the upper versus lowest AHI quartile (7.6 vs 7.1, p 0.042). CONCLUSION Our data do not support the presence of a strong link between CRP levels and the presence and severity of OSA in obese patients. CRP appears mostly linked to obesity and, in the obese female, to glucose metabolism.