[Relationship between obstructive sleep apnea-hypopnea syndrome and high sensitivity C-reactive protein in non-obese subjects].

Objective To evaluate the relationship between high sensitivity C-reactive protein (hs-CRP) level and the severity of obstructive sleep apnea-hypopnea syndrome (OSAHS) in non-obese patients. Methods A total of 65 patients with suspected OSAHS were recruited.Those with a history of cardiovascular or cerebrovascular events, arterial hypertension, chronic obstructive pulmonary disease, diabetes mellitus and smoking were excluded.All subjects were examined by polysomnography.Subjects with an apnea-hypopnea index (AHI) ≥5 were considered to have OSAHS.They were divided into mild, moderate and severe OSAHS groups and those with an AHI<5 were accepted into the control group.The serum level of hs-CRP,a biomarker for cardiovascular disease, was measured with peripheral venous blood samples. Results There were 53 males and 12 females with a mean age 44.3±12.2 years and a body mass index (BMI) <25 kg/m2.The serum levels of hs-CRP were significantly higher in OSAHS patients than those of the controls (geometric mean[95% confidence interval]0.416[0.288-0.600]vs 0.749[0.559-1.003] mg/L, P<0.05).Mean levels of hs-CRP did not differ between the group with mild-to-moderate OSAHS and the control group.However, the severe OSAHS group had a higher level of hs-CRP than the control group (P=0.004).A significant positive relationship existed between hs-CRP and AHI (r=0.407, P=0.001).According to stepwise multivariate analysis, only AHI was a reliable predictor for elevated serum level of hs-CRP among all these related factors (R2=0.166, P=0.001). Conclusion The severity of OSAHS is associated with an elevated serum level of hs-CRP in non-obese patients. Key words: Sleep apnea, obstructive; C-reactive protein; Obesity;  Cardiovascular diseases