Objective: Although circulating oxidized LDL (oxLDL) is elevated in persons with coronary heart disease (CHD), whether oxLDL is elevated in persons with high CHD risk before any events is unknown. Therefore, we studied the association between high, predicted CHD risk and oxLDL in the Health ABC cohort.
Methods and results: This cohort included 385 persons with CHD and 1183 persons at high risk; the latter were all persons with CHD risk equivalents: noncoronary forms of clinical atherosclerotic disease, diabetes, and a 10-year risk for CHD >20% by Framingham scoring. The remaining 1535 participants were at low risk. Levels of oxLDL were 1.18+/-0.61 mg/dL for low-risk persons, 1.50+/-0.81 mg/dL for high-risk persons without diagnosed CHD, and 1.32+/-0.83 mg/dL for persons with CHD (P<0.001). The odds ratio for high CHD risk in the highest quintile of oxLDL, compared with the lowest quintile and after adjusting for age, sex, race, LDL cholesterol, smoking status, and C-reactive protein, was 2.79 (P<0.001).
Conclusions: The odds ratio for elevated oxLDL among persons with high CHD risk before any CHD events was higher than that among persons with established CHD. A likely explanation is that once CHD is diagnosed, individuals are frequently treated with a statin, which is associated with lowering of LDL cholesterol and oxLDL levels.