Background and objective: High-resolution B-mode ultrasound measurements of carotid intima-media thickness (IMT) and determination of plaque presence are useful to assess preclinical atherosclerosis. Normal IMT values have not been reported in Spanish subjects. Our aim was to define normality data of carotid ultrasound by sex and age.
Subjects and methods: We studied 250 healthy, normolipidemic subjects, 125 men and 125 women, with mean age 49 years (range, 20-81). We assessed cardiovascular risk factors and performed ultrasound determination of mean and maximum IMT in the far wall of the common carotid artery, plaque occurrence, and maximum plaque height.
Results: Reference values for carotid IMT, expressed as 25th, 50th, and 75th percentiles by sex and 5 age groups, have been obtained. The 50th percentiles of mean IMT ranged from 0.50 to 0.74 mm in men in the age groups 35 years or younger and 65 years or older, respectively. For women, corresponding IMT values ranged from 0.40 to 0.65 mm. IMT was strongly related (p < 0.001) to age, both in men (r = 0.57) and women (r = 0.61). From the regression equations, the estimated yearly increase in IMT was 0.005 mm in men and 0.007 mm in women. More than 50% of men aged 55 years and older, and of women aged 65 years and older, had carotid plaques.
Conclusions: Both IMT and plaque frequency were associated with age in men and women. Carotid IMT values in a Spanish community cohort were lower than those reported for countries with higher cardiovascular risk, such as Northern European countries and the US.