WOMEN HAVE A LARGER AND LESS ATHEROGENIC LOW-DENSITY-LIPOPROTEIN PARTICLE-SIZE THAN MEN

Some epidemiological studies have shown that serum total cholesterol i ncreases with age, especially in women. On the other hand, the risk of coronary artery disease is smaller in women than in men. Earlier stud ies have shown that a small dense low density lipoprotein (LDL) is mor e atherogenic than a large LDL. We studied LDL size and apolipoprotein E (apo E) phenotypes in premenopausal and postmenopausal women and in men at the same age. In this study 342 subjects participating in a he alth screening study were examined. There were four subgroups: 40-year -old men (n = 85), 40-year-old women (n = 80), 70-year old men (n = 88 ) and 70-year-old women (n = 89). In the present study LDL size was la rger (P < 0.01) in women (26.39 +/- 0.07 nm) than in men (25.95 +/- 0. 07 nm). We found that LDL size correlated highly positively (r = 0.606 ; P < 0.001) with serum high density lipoprotein (HDL) concentration a nd inversely with serum triglyceride concentration (r = -0.627; P < 0. 001). Measuring serum HDL cholesterol and triglycerides in health scre ening studies gives information indirectly about LDL size and its athe rogenicity. Apo E phenotype was not significantly associated with seru m triglycerides, but was associated with LDL size, LDL cholesterol, to tal cholesterol and HDL cholesterol. In our sample LDL size decreased and LDL cholesterol and total cholesterol increased according to the m ost prevalent apo E phenotypes in the order E2/3, E3/3, E3/4 and E4/4. Subjects with phenotype apo E4/4 had the smallest LDL size (25.70 +/- 0.19 nm), the highest total cholesterol (6.53 +/- 0.35 mmol/l) and th e lowest HDL cholesterol values (1.28 +/- 0.04 mmol/l). We conclude th at there was a;significant interaction between sex and age in serum to tal cholesterol which was highest in older women. However, their LDL s ize was larger and their LDL is less atherogenic. Apo E phenotype had a significant influence on LDL size.