Myeloperoxidase is associated with incident coronary heart disease independently of traditional risk factors: results from the MONICA/KORA Augsburg study

Aims: Oxidative stress plays a critical role in the initiation and progression of atherosclerosis. Myeloperoxidase (MPO) is a marker of oxidative stress. We prospectively investigated whether an increased serum concentration of MPO is associated with an increased risk of incident coronary heart disease (CHD).

Methods: We conducted a population-based case-cohort study in middle-aged, healthy men and women within the MONICA/KORA Augsburg studies. Serum levels of MPO were measured in 333 subjects with (cases) and 1727 without (noncases) incident CHD. Mean follow-up time was 10.8 ± 4.6 years.

Results: Baseline concentrations of MPO were higher in cases compared with noncases (P ≤ 0.001 in men; P=0.131 in women). After adjustment for major cardiovascular risk factors, the hazard ratio (HR) with 95% confidence interval (CI) comparing the top with the two lower tertiles was 1.70 (95% CI, 1.25-2.30). After additional adjustment for markers of inflammation and endothelial dysfunction, the association was attenuated (HR 1.50; 95% CI, 1.08-2.09). There were no significant interactions of MPO with sex or increased weight on CHD risk.

Conclusions: Elevated concentrations of the oxidative stress marker MPO were independently associated with increased risk of incident CHD. This finding deserves detailed evaluation in further studies.