[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/m(2). 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 (R(2) = 0.166, P = 0.001).
Conclusion: The severity of OSAHS is associated with an elevated serum level of hs-CRP in non-obese patients.