Oxidation of LDL and extent of peripheral atherosclerosis

Evidence has accumulated for oxidative modification of low-density lipoprot eins (LDL) to play an important role in the atherogenic process. Therefore, we investigated the relation between susceptibility of LDL to oxidation an d risk of peripheral atherosclerosis among 249 men between 45 and 80 years of age. The ankle-arm index was calculated for both legs as the ratio of sy stolic blood pressure in the leg divided by the arm systolic blood pressure . The lowest of both ankle-arm indices was used to categorize subjects. Thi rty-nine men with an ankle-arm index <1.00 (20% cut-off point of distributi on) were classified as subjects with peripheral atherosclerosis. Subjects with peripheral atherosclerosis reported more often the use of a s pecial diet and the use of antihypertensive medication, aspirin and coumari n derivatives. No significant differences in total, LDL and HDL cholesterol and triglycerides were present between groups. Resistance time and maximum rate of oxidation were measured ex vivo using copper-induced LDL oxidation . Subjects with peripheral atherosclerosis had a significantly lower resist ance time, whereas the maximum rate of oxidation tended to be increased in subjects with peripheral atherosclerosis. Odds ratios (ORs, and 95% confide nce interval) for the successive tertiles of resistance time were 1.00 (ref erence), 0.37 (0.15-0.89) and 0.37 (0.16-0.86) (P-trend < 0.01) ORs for the successive tertiles of maximum rate of oxidation were 1.00 (reference), 1. 34 (0.47-3.82) and 1.50 (0.55-4.15). This inverse association was borderlin e significant (P-trend = 0.07). These results support an association between LDL oxidation and the developm ent of peripheral atherosclerosis.