Serum Myeloperoxidase Levels Are Associated With the Future Risk of Coronary Artery Disease in Apparently Healthy Individuals: The EPIC-Norfolk Prospective Population Study

Objectives We evaluated whether serum myeloperoxidase (MPO) levels are associated with the risk of future development of coronary artery disease (CAD) in apparently healthy individuals. Background An enzyme of the innate immune system, MPO exhibits a wide array of proatherogenic effects. These include induction of oxidative damage to low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol and promotion of plaque vulnerability. Recent studies revealed that MPO independently predicts adverse outcomes in patients with chest pain or suspected acute coronary syndrome. Methods Myeloperoxidase was measured in baseline samples of a case-control study nested in the prospective EPIC (European Prospective Investigation into Cancer and Nutrition)-Norfolk population study. Case subjects (n = 1,138) were apparently healthy men and women who developed CAD during 8-year follow-up. Control subjects (n = 2,237), matched for age, gender, and enrollment time, remained free of CAD. Results The MPO levels were significantly higher in case subjects than in control subjects and correlated with C-reactive protein (CRP) (ρ = 0.25; p 728 pmol/l) similarly predicted increased risk of future CAD among participants with either LDL-cholesterol 50 mg/dl, or CRP Conclusion Elevated MPO levels predict future risk of CAD in apparently healthy individuals. This study suggests that inflammatory activation precedes the onset of overt CAD by many years.