title: Myeloperoxidase, subclinical atherosclerosis, and cardiovascular disease events.
abstract: OBJECTIVE
  We evaluated whether myeloperoxidase (MPO) predicts future cardiovascular disease (CVD) events in asymptomatic adults and whether subclinical atherosclerosis may affect this relation.
  
  
  BACKGROUND
  Myeloperoxidase is a leukocyte-derived enzyme-generating reactive oxidant species that has been shown to predict risk of CVD in selected populations.
  
  
  METHODS
  We studied 1,302 asymptomatic adults (mean age 59 years, 47% women) without known CVD who were followed for 3.8 years. We measured MPO by the use of immunoassay. Coronary artery calcium (CAC), a measure of subclinical atherosclerosis, was measured by computed tomography with the Agatston score categorized as none/minimal (0 to 9), mild (10 to 99), and moderate/significant (> or = 100). Cox regression, adjusted for age, sex, and other risk factors, examined the relation of CAC and/or MPO with incident CVD events.
  
  
  RESULTS
  Persons with MPO levels at or above compared with below the median (257 pM) were more likely (p < 0.05 to p < 0.001) to be women, have a higher body mass index, greater low-density lipoprotein cholesterol, greater systolic and diastolic blood pressure, and lower high-density lipoprotein cholesterol. Mean MPO levels increased according to CAC categories (p trend = 0.02). Incident CVD events were more likely in those at or above versus below the median MPO level (4.6% vs. 2.3%, p = 0.02), even after adjustment for age, sex, CAC, and risk factors (hazard ratio [HR]: 1.9, 95% confidence interval: 1.0 to 3.6, p = 0.04). Combining CAC and MPO categories, CVD incidence ranged from 0.6% in those with a CAC score of 0 to 9 to 7.1% (adjusted HR: 9.2, p < 0.001) in those with CAC scores of > or = 100 and MPO below the median and 14.0% (adjusted HR: 19.5, p < 0.0001) in those with CAC scores of > or = 100 and MPO at or above the median.
  
  
  CONCLUSIONS
  Our study suggests persons with both increased levels of both MPO and CAC are at an increased risk of CVD events. Imaging of subclinical atherosclerosis combined with assessment of biomarkers of plaque vulnerability may help improve CVD risk stratification.
authors.affiliation: Division of Cardiology, University of California, Irvine, California, USA.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Wong
authors.forename: Heidi
authors.initials: H
authors.lastname: Gransar
authors.forename: Jagat
authors.initials: J
authors.lastname: Narula
authors.forename: Leslee
authors.initials: L
authors.lastname: Shaw
authors.forename: Johanna H
authors.initials: JH
authors.lastname: Moon
authors.forename: Romalisa
authors.initials: R
authors.lastname: Miranda-Peats
authors.forename: Alan
authors.initials: A
authors.lastname: Rozanski
authors.forename: Sean W
authors.initials: SW
authors.lastname: Hayes
authors.forename: Louise E J
authors.initials: LE
authors.lastname: Thomson
authors.forename: John D
authors.initials: JD
authors.lastname: Friedman
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Berman
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000032:analysis; D002114:Calcinosis / Q000150:complications / Q000000981:diagnostic imaging / Q000201:enzymology*; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging / Q000201:enzymology / Q000209:etiology*; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging / Q000201:enzymology*; D005260:Female; D006801:Humans; D007118:Immunoassay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D009195:Peroxidase / Q000032:analysis*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D009195:Peroxidase