Regulation of small dense LDL concentration in Korean and Scottish men and women

Abstract

Small dense LDL is now emerging as an important risk factor for coronary artery disease. The amount of the LDL III has been reported to differ between ethnic groups. To investigate differences in the distribution of LDL subfractions between Korean and Scottish populations, we measured the plasma concentration and percent distribution of three major LDL subfractions in age-and sex-matched, middle aged, healthy 124 Korean and Scottish subjects (32 Korean men vs. 32 Scottish men; 30 Korean women vs. 30 Scottish women). Body mass index and waist circumference did not differ between the two ethnic groups. Total cholesterol and LDL cholesterol concentrations were higher in Scottish men compared with Korean men ( P<0.01), while plasma triglyceride concentration was higher in Korean men and women ( P<0.01 in men, P<0.05 in women). HDL cholesterol concentrations in both Korean men and women were lower than that of their Scottish counterparts ( P<0.05 in men; P<0.001 in women). Korean men had lower concentrations of total LDL (242±65 vs. 325±122 mg/dl, P<0.01), LDL I (24±18 vs. 60±36 mg/dl, P<0.001) and LDL II (110±56 vs. 196±78 mg/dl, P<0.001). In contrast, LDL III concentration was markedly higher in Korean men (108±75 vs. 70±65 mg/dl, P<0.05). Likewise, the percent of LDL I (10.0±7.3 vs. 19.1±10.1%, P<0.001) and LDL II (47.2±20.7 vs. 60.1±10.9%, P<0.01) were lower in Korean men, while that of LDL III was higher (42.8±24.9 vs. 20.8±15.0%, P<0.001). In the female population, there were no differences in total LDL and LDL I concentrations between Korean and Scottish. LDL II concentration was lower in Korean women (106±53 vs. 151±57 mg/dl, P<0.01). Korean women showed a higher percent of LDL III (24.8±24.7 vs. 14.2±5.9%, P<0.05) and a lower LDL II (47.8±19.1 vs. 61.0±10.0%, P<0.01). Multiple linear regression revealed that plasma triglyceride concentration was the most important determinant of the LDL III subfraction concentration in Korean men and women and in Scottish men. In Korean men, the LDL III concentration rose linearly through the whole range of plasma triglyceride concentration, whereas in Scottish men, there was a threshold at 108 mg/dl triglyceride above which there was a positive association. Korean women showed the same pattern as Scottish men. We suggest that LDL concentrations and LDL subfraction distributions are regulated differently in these two ethnic groups. The different relationships between triglyceride and LDL III subfraction in Koreans versus Scots suggest that other factors, such as hepatic lipase or cholesteryl ester transfer protein may additionally play a role determining the LDL subfraction profile.