OBJECTIVE - The goal of this study was to compare and contrast coronary artery calcium (CAC) with abdominal aortic calcium (AAC) in terms of their associations with traditional and novel cardiovascular disease (CVD) risk factors.
METHODS AND RESULTS - We measured both AAC and CAC using computed tomography scans in 1974 men and women aged 45 to 84 years from a multiethnic cohort. Traditional and novel CVD risk factors were examined separately in relation to AAC and CAC, using logistic regression for qualitative categorical comparisons and multiple linear regression for quantitative continuous comparisons. AAC was significantly associated with cigarette smoking and dyslipidemia and showed no gender difference. In contrast, CAC showed much weaker associations with smoking and dyslipidemia and a strong male predominance. Age and hypertension were associated similarly and significantly with AAC and CAC. Novel risk factors generally showed no independent association with either calcium measure, although in subset analyses, phosphorus, but not calcium, was related to CAC. The receiver operating characteristic curves for the qualitative results and the r(2) values for the quantitative analyses were both much higher for AAC than for CAC.
CONCLUSIONS - AAC showed stronger correlations with most CVD risk factors than did CAC. The predictive value of AAC compared with CAC for incident CVD events remains to be evaluated.