Abstract: Objective To investigate serum succinate levels and its effect on the risk of cardiovascular disease in patients with obstructive sleep apnea hypopnea syndrome(OSAHS). 
Methods Eighty-five patients(including 38 cases in the mild to moderate group and 47 cases in the severe group) with OSAHS were enrolled consecutively, and 25 healthy controls matched for age, gender, smoking and drinking at baseline were selected. Expression levels of serum succinate were compared between patients with OSAHS and healthy controls, and framingham risk score(FRS)was compared among patients with OSAHS. Univariate regression analysis was applied to clarify the effects of each indicator on FRS, and multiple linear stepwise regression was used to clarify the independent effect of succinate on FRS. 
Results Serum succinate levels were significantly higher in patients with OSAHS than in healthy controls, which increased with the severity of disease. Univariate regression analysis revealed that succinate and apnea-hypopnea index were significantly and positively correlated with FRS, while the lowest oxygen saturation and mean oxygen saturation were significantly and negatively correlated with FRS(P＜0.05). The results of multiple linear regression analysis showed that the serum succinate level was an independent influencing factor of FRS in patients with OSAHS. 
Conclusion Serum succinate levels are strongly associated with the risk of cardiovascular disease.

Key words: cardiovascular diseases, succinic acid, sleep apnea, obstructive