A case-control study of oxidized low density lipoproteins and preeclampsia risk

Diffuse vascular endothelial dysfunction, secondary to oxidative stress, is an important pathological feature of preeclampsia. Oxidative conversion of low density lipoproteins (LDL) to oxidized-LDL (Ox-LDL) is considered an important step in transforming macrophages into lipid-laden foam cells destined to develop into early atherosclerotic-like lesions. In our study of 95 women with preeclampsia and 100 controls, we evaluated the association between maternal plasma Ox-LDL concentrations and preeclampsia risk. Ox-LDL concentrations were measured using a solid phase two-site enzyme immunoassay. Plasma lipids were measured using standard enzymatic procedures. We used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for confounders. Plasma Ox-LDL concentrations were positively correlated with cholesterol, triglyceride (TG), and LDL concentrations in cases and controls, (Spearman's r ranging from 0.39-0.48, p-values all < 0.01). There was no evidence of an increased risk of preeclampsia across increasing quartiles of Ox-LDL. The ORs for successive quartiles, with the lowest as the reference group, were as follows: 1.0, 1.1, 0.6, and 1.2. Women with extremely high concentrations of Ox-LDL (≥ 73 U/L, the upper decile), as compared with those with lower values (< 73 U/L) had a 2.7-fold increased risk of preeclampsia (95% CI 1.0-6.8). Women with high Ox-LDL and high TG concentrations (≥ 284 mg/dl), as compared with those without these two factors, had a 9.6-fold increased preeclampsia risk (95% CI 2.0-45.6). Elevated Ox-LDL, particularly in conjunction with elevated TG, appears to be a risk factor of preeclampsia.