Relation of Risk Factors and Abdominal Aortic Calcium to Progression of Coronary Artery Calcium (from the Framingham Heart Study)

Coronary artery calcium (CAC) and abdominal aortic calcium (AAC) on multidetector computed tomography (MDCT) permit assessment of the presence and burden of coronary and systemic atherosclerosis. Risk factors for progression of CAC and AAC and the association of AAC with CAC progression have not been well characterized in a community-dwelling cohort. We studied 1,959 asymptomatic participants from the Framingham Heart Study who underwent serial MDCT scans with a median interval of 6.1 years. Primary outcomes were (a) the incidence of CAC and AAC (CAC >0 and AAC >0 with baseline CAC = 0 and AAC = 0) and (b) absolute progression of CAC (CAC > baseline CAC and AAC > baseline AAC). Covariates were collected at adjacent cycle examinations and included age, gender, use of antihypertensive therapy, use of lipid-lowering therapy, cigarette smoking, and total and high-density lipoprotein cholesterol. Predictors for CAC and AAC progression included baseline CAC, baseline AAC, lipid-lowering therapy, diabetes, high-density lipoprotein cholesterol, BMI, and serum creatinine. Multivariable stepwise logistic and linear regression models were used to test the association of these risk factors with CAC and AAC. Those who developed incident CAC on follow-up scanning comprised 18.8% of 1,124 participants, and 84.9% of 780 participants, with detectable baseline CAC, had further progression. Baseline AAC was a predictor of both CAC incidence and progression, independent of other risk factors. In stepwise models, addition of baseline AAC slightly improved the area under the curve from 0.72 (0.68 to 0.76) to 0.74 (0.70 to 0.78). In conclusion, standard cardiovascular disease risk factors are associated with incidence and progression of CAC and AAC, and AAC augments CAC incidence and progression above cardiovascular disease risk factors.