Tracking of coronary artery calcium (CAC) has been suggested for
monitoring the effects of lipid control, but it is not known whether
lipid control decreases progression of CAC. Seven hundred sixty-one
subjects (mean age 64.5 +/- 7.3 years; 91% men; 69% positive for CAC)
in an ongoing cohort study underwent baseline and follow-up (after 7.0
+/- 0.5 years) computed tomography for CAC. Subjects were stratified
into low-risk (<2 risk factors), intermediate-risk (> or =2 risk
factors but <20% risk of coronary heart disease over 10 years), or
high-risk (> or =2 risk factors and >20% risk of coronary heart
disease in 10 years or diabetes) groups. Lipid control was defined
according to criteria of the National Cholesterol Education Program.
Two-way analysis of covariance was used to examine the relation of
low-density lipoprotein (LDL) cholesterol and risk group to change in
CAC volume score. Control of levels of high-density lipoprotein (HDL)
cholesterol and triglycerides was also examined in relation to
progression of CAC. After adjustment for other risk factors and
baseline CAC volume, CAC progression was similar between those with
adequate and those with inadequate control of LDL cholesterol (p =
0.68) and across categories of optimal, intermediate, and higher risk
LDL cholesterol (p = 0.40). However, higher levels of HDL cholesterol
(> or =1.5 mmol/L [60 mg/dl]) were associated with less progression
of CAC volume (151 vs 203 mm(3) in those with HDL cholesterol <1.0
mmol/L [40 mg/dl], p = 0.03). There was no relation between
triglycerides and CAC progression (p = 0.54). Our findings do not
support the use of CAC assessment for monitoring the control of LDL
cholesterol, but greater progression of CAC may occur in those in whom
HDL cholesterol is not controlled. |