Abstract: Objective: The aim of the study was to explore the association of different （low density lipoprotein,LDL）subtypes with coronary artery disease (CAD) in different age groups. Methods: A total of 256 subjects with CAD who were diagnosed by coronary angiography and hospitalized in the department of Cardiology, Affiliated Hospital of Chengde Medical College from September 2018 to November 2019 were continuously enrolled in this study, and all of them were divided into the young and middle-aged CAD group (n = 150, age <65 years) and elderly CAD group (n = 106, age ≥65 years). Quantitative analysis of LDL subtypes were performed by gel electrophoresis. Spearmen rank correlation was used to analyze the correlation among LDL subtypes and AIP. The multiple linear regression analysis was used to analyze each LDL subtype as an independent predictor of AIP. Results: The median of AIP in young CAD group was higher than the elderly CAD group (P <0.05). The correlation of the large-buoyant LDL and its subtypes LDL1, LDL2, the intermediate LDL subtype LDL4 and the small-dense LDL and its subtype LDL5 with AIP was greater in the elderly group (all P <0.05). large-buoyant LDL and its subtypes LDL1, LDL2 are independent negative predictors of AIP in CAD patients, intermediate LDL subtypes LDL4 and small-dense LDL and its subtype LDL5 are independent positive predictors of AIP in CAD patients (all P <0.05). Conclusion: The correlations of different LDL subtypes with CAD prevalence in young and middle-aged and elderly-aged populations were different, and the risk of predicting CAD were also different, especially in elderly patients.

Key words: lipoproteins, LDL, coronary disease, low density lipoprotein subtype, atherosclerotic index of plasma