Coronary artery calcium score, risk factors, and incident coronary heart disease events.
BACKGROUND
Whether the absence of coronary artery calcium, or conversely the presence of high volumes of coronary artery calcium, may alter assessment of coronary heart disease risk based on traditional risk factors is uncertain. We sought to identify a potential threshold of coronary artery calcium for clinical use and examine the predictive power of coronary artery calcium in individuals categorized using conventional coronary heart disease risk assessment.


METHODS
The study included 10,746 men and women (36.3%) with a mean age of 53.8+/-9.9 years who were either physician- or self-referred for electron beam tomography scanning to a preventive medical clinic. Coronary heart disease risk factors were elicited by use of a questionnaire.


RESULTS
During a mean follow-up of 3.5 years, 81 primary events (coronary heart disease death or nonfatal myocardial infarction) occurred. Among individuals with a coronary artery calcium score of zero, the primary event rate was very low (0.4 events per 1000 person-years of observation). When participants were stratified by self-reported coronary heart disease risk factors (0-2, or 3-4), a coronary artery calcium score >or=100 was associated with substantially increased risk of coronary heart disease events within each level of stratification. In a subgroup of participants with available clinical data, similar results were found when participants were categorized by Framingham risk scores.


CONCLUSIONS
Coronary artery calcium score can identify individuals at increased risk for coronary heart disease events who otherwise would be considered low-risk based on clinical assessment. A coronary artery calcium score of zero is associated with very low risk for coronary heart disease in the short to intermediate term ( approximately 3.5 years) regardless of the number of risk factors present.
Church
Timothy S
TS
The Cooper Institute, Dallas, TX 75230, United States. tchurch@cooperinst.org
Levine
Benjamin D
BD
McGuire
Darren K
DK
Lamonte
Michael J
MJ
Fitzgerald
Shannon J
SJ
Cheng
Yiling J
YJ
Kimball
Thomas E
TE
Blair
Steven N
SN
Gibbons
Larry W
LW
Nichaman
Milton Z
MZ
D000328:Adult; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000517:prevention & control; D002118:Calcium / Q000378:metabolism; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000517:prevention & control; D003331:Coronary Vessels / Q000378:metabolism / Q000473:pathology*; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000453:epidemiology; D006973:Hypertension / Q000453:epidemiology; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D012307:Risk Factors; D014057:Tomography, X-Ray Computed
D002118:Calcium