AimTo study the relationship between serum paraoxonase-1(PON1) activity and glycosylated hemoglobin (HbA1c), coronary artery lesions in patients with coronary heart disease.MethodsA total of 133 patients with suspected diagnosis of coronary artery disease,according to the coronary angiography results, were divided into coronary heart disease group(n=101) and control group (n=32).According to HbA1c levels, 101 cases of coronary heart disease were divided into three sub-groups: group A 31 cases (HbA1c<6.5%), group B 41 cases (6.5%≤HbA1c<9%), group C 29 cases (HbA1c≥9%).Serum PON1 activity was measured spectrophotometrically, and coronary lesions were detected by Gensini integral result.PON1 activity and Gensini integral among groups were compared, relationship between PON1 activity and HbA1c level, coronary lesions degree was analysed.ResultsSerum PON1 activity in the coronary heart disease group (2.17+0.18) was significantly lower than that in control group (2.49+0.19,p<0.01); PON1 activity in group C declined obviously (p<0.01) and coronary stenosis Gensini integral increased (p<0.01) compared with group A, in group C PON1 activity had fallen (p<0.05) and coronary stenosis Gensini integral increased (p<0.05) compared with group B.The correlation analysis showed that the serum PON1 activity was negatively related to HbA1c levels (r=－0.534,p<0.01), and negatively related to Gensini integral (r=－0.742,p<0.01).