[Total cholesterol mediates the effect of ABO blood group on coronary heart disease]

To find a potential link among ABO blood group, lipid profiles and coronary artery disease (CAD) and to estimate the effect size of connection using mediation analysis model.

A total of 898 consecutive patients undergoing coronary angiography were enrolled, and divided into CAD group and non-CAD group according to angiographic findings. According to ABO blood group, patients were divided into O blood group and non-O blood group, as well as A blood group and non-A blood group. Baseline characteristics among various groups were compared and the association of ABO blood group, CAD and lipid profile was explored.

Subjects of blood type A had higher concentration of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) compared with that of non-A type (TC: (4.43 ± 1.12) mmol/L vs. (4.18 ± 1.09) mmol/L, LDL-C: (2.79 ± 0.99) mmo/L vs. (2.59 ± 1.01) mmol/L, all P < 0.01). TC and LDL-C were significantly higher while high density lipoprotein cholesterol (HDL-C) and ApoA I levels were significantly lower in CAD group than in non-CAD group (TC: (4.36 ± 1.05) mmol/L vs. (4.13 ± 1.16) mmol/L, LDL-C: (2.61 ± 0.87) mmol/L vs. (2.47 ± 0.94) mmol/L; ApoA I: (1.38 ± 0.29) mmol/L vs. (1.45 ± 0.33) mmol/L; all P < 0.01). After adjustment for traditional cardiovascular risk factors, blood group A and TC remained significantly associated with the risk of CAD (OR = 1.88, 95% CI 1.280-2.774, P < 0.01; OR = 1.03, 95% CI 1.018-1.033, P < 0.01, respectively). Specially, mediation analysis indicated that 10.5% of the effect of A blood group on CAD was mediated by TC levels (P < 0.01).

Our data indicate that there is an association between ABO blood group, TC levels and risk of CAD. Around 10.5% of the effect of A blood group on CAD is mediated by TC levels.