title: Impact of coronary artery calcium on coronary heart disease events in individuals at the extremes of traditional risk factor burden: the Multi-Ethnic Study of Atherosclerosis.
abstract: OBJECTIVE
  We sought to evaluate the impact of coronary artery calcium (CAC) in individuals at the extremes of risk factor (RF) burden.
  
  
  RESULTS
  6698 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA) were followed for coronary heart disease (CHD) events over mean 7.1 ± 1 years. Annualized CHD event rates were compared among each RF category (0, 1, 2, or ≥3) after stratification by CAC score (0, 1-100, 101-300, and >300). The following traditional modifiable RFs were considered: cigarette smoking, LDL cholesterol ≥3.4 mmol/L, low HDL cholesterol, hypertension, and diabetes. There were 1067 subjects (16%) with 0 RFs, whereas 1205 (18%) had ≥3 RFs. Among individuals with 0 RFs, 68% had CAC 0, whereas 12 and 5% had CAC >100 and >300, respectively. Among individuals with ≥3 RFs, 35% had CAC 0, whereas 34 and 19% had CAC >100 and >300, respectively. Overall, 339 (5.1%) CHD events occurred. Individuals with 0 RFs and CAC >300 had an event rate 3.5 times higher than individuals with ≥3 RFs and CAC 0 (10.9/1000 vs. 3.1/1000 person-years). Similar results were seen across categories of Framingham risk score.
  
  
  CONCLUSIONS
  Among individuals at the extremes of RF burden, the distribution of CAC is heterogeneous. The presence of a high CAC burden, even among individuals without RFs, is associated with an elevated event rate, whereas the absence of CAC, even among those with many RF, is associated with a low event rate. Coronary artery calcium has the potential to further risk stratify asymptomatic individuals at the extremes of RF burden.
authors.affiliation: The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, Baltimore, MD, USA Brigham and Women's Hospital, Cardiovascular Division, Boston, MA, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Silverman
authors.affiliation: The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, Baltimore, MD, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Blaha
authors.affiliation: Section of Cardiovascular Medicine and the Robert Wood Johnson Clinical Scholars Program, Department of Internal Medicine, Yale University School of Medicine, and Section of Health Policy and Administration, Yale School of Public Health; and the Center for Outcomes Research and Evaluation, Yale-New Haven Hospital, New Haven, CT, USA.
authors.forename: Harlan M
authors.initials: HM
authors.lastname: Krumholz
authors.affiliation: Los Angeles Biomedical Research Institute at Harbor-UCLA, Torrance, CA, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Budoff
authors.affiliation: Brigham and Women's Hospital, Cardiovascular Division, Boston, MA, USA.
authors.forename: Ron
authors.initials: R
authors.lastname: Blankstein
authors.affiliation: National Institutes of Health, Bethesda, MD, USA.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Sibley
authors.affiliation: Center for Prevention and Wellness Research, Baptist Health Medical Group, 1691 Michigan Avenue, Suite 500, Miami Beach, FL 33139, USA.
authors.forename: Arthur
authors.initials: A
authors.lastname: Agatston
authors.affiliation: The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, Baltimore, MD, USA.
authors.forename: Roger S
authors.initials: RS
authors.lastname: Blumenthal
authors.affiliation: The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, Baltimore, MD, USA Center for Prevention and Wellness Research, Baptist Health Medical Group, 1691 Michigan Avenue, Suite 500, Miami Beach, FL 33139, USA Department of Medicine, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida Department of Epidemiology, Robert Stempel College of Public Health, Florida International University, Miami, Florida khurramn@baptisthealth.net knasir1@jhmi.edu.
authors.forename: Khurram
authors.initials: K
authors.lastname: Nasir
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000453:epidemiology*; D003327:Coronary Disease / Q000453:epidemiology; D017281:Cost of Illness; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D061205:Vascular Calcification / Q000453:epidemiology*
keywords: Coronary artery calcium; Coronary heart disease; Risk factors