RISK-FACTORS AND SEGMENT-SPECIFIC CAROTID ARTERIAL ENLARGEMENT IN THEATHEROSCLEROSIS RISK IN COMMUNITIES (ARIC) COHORT

Background and Purpose B-mode ultrasound imaging affords the opportuni ty to quantify both intimal-medial thickness (IMT) and lumen diameter of extracranial carotid arteries in ambulatory populations. Since the relation of IMT to lumen diameter may be complex, we asked whether car diovascular disease risk factors (previously shown to be associated wi th greater arterial IMT) are related to smaller lumen diameters. Metho ds We used B-mode ultrasound to quantify lumen diameter, interadventit ial diameter, and IMT of the extracranial carotid arteries and assesse d the relationship of these measures to body mass index, smoking, low- density lipoprotein (LDL) and high-density lipoprotein cholesterol, hy pertension, and diabetes in 6088 male and 7493 female participants in the Atherosclerosis Risk in Communities (ARIC) cohort. Results Smoking , hypertension, and LDL cholesterol were consistently related to great er IMT in the common and internal carotid arteries of men and women, a s has been previously reported. In the internal carotid artery: smokin g, hypertension, and LDL cholesterol were consistently related to smal ler lumens. In the common carotid artery, body mass index, smoking, an d hypertension were related to significantly larger, and LDL cholester ol to smaller, lumens. Thus, only LDL cholesterol was consistently ass ociated with smaller lumens in both the common and internal carotid ar teries. Conclusions Risk factors relate positively to IMT in both the common and internal carotid arteries and inversely with lumen diameter in the internal carotid artery, in parallel with their relation to cl inical events. However. their association with lumen diameters of the common carotid artery in population-based samples is more complex, and in some cases adverse levels of risk factors map be associated with l arger lumens.