Although risk factors for coronary artery disease are also associated with increased
carotid artery intima-media thickness (IMT) as measured by B-mode ultrasonography
in middle-aged and older persons, information on the impact of multiple risk factors
on the IMT of different segments of the carotid artery in young adults is limited.
This relation was examined in a sample of 518 black and white subjects (mean age 32
years; 71% white, 39% male) enrolled in the Bogalusa Heart Study. IMT was thicker
and more skewed in the bulb compared with other carotid segments. Race differences
(blacks more than whites) were noted for the common carotid (p <0.001) and carotid
bulb (bifurcation) IMT (women only, p <0.001). Men had a greater IMT in the common
carotid (p <0.05), internal carotid (p <0.05), and carotid bulb (whites only, p <0.001).
In a multivariate analysis, systolic blood pressure, race, age, low-density lipoprotein
(LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol weree entered into
a model in that order and accounted for the 16.7% variance in the common carotid IMT;
age, systolic blood pressure, HDL cholesterol, LDL cholesterol, race, and insulin
levels explained the 19.4% variance in the carotid bulb IMT. Gender and body mass
index (BMI) accounted for the 4.7% variance in the internal carotid IMT. Increases
in IMT with increasing number of risk factors (cigarette smoking, higher total cholesterol
to HDL cholesterol ratio, higher systolic blood pressure, greater waist circumference,
and higher insulin level) were noted for the common carotid and carotid bulb segments
(p for trend <0.001 for both). The observed deleterious trend of increasing IMT at
different carotid segments with increasing number of risk factors in free-living,
asymptomatic young subjects underscores the importance of profiling multiple risk
factors early in life. Ultrasonography of carotid arteries, especially at the bifurcation,
may be helpful along with measurements of risk factors for evaluation of asymptomatic
atherosclerotic disease.