Reference values of carotid artery intima-media thickness and association with atherosclerotic risk factors in healthy subjects in Korea

Cho, You Lee; Kim, Dae Jung; Kim, Ha Dong; Choi, Sung Hee; Kim, Su Kyung; Kim, Hyung Jin; Ahn, Chul Woo; Cha, Bong Soo; Lim, Sung Kil; Kim, Kyung Rae; Lee, Hyun Chul; Huh, Kap Bum

Abstract

BACKGROUND: Atherosclerosis is an important cause of cardiovascular and cerebrovascular diseases, which are the major cause of death in middle-aged and older adults. However atherosclerotic lesions are not easily detected before they cause symptoms and signs which means that early detection is important. In Korea it has been reported that the carotid artery intima-media thickness (IMT) correlates well with the atherosclerotic risk factors in type 2 diabetes mellitus, but there is little data available on the carotid artery IMT in healthy subjects. Therefore, the aims of this study were to determine the reference values of the carotid artery IMT in healthy subjects and to investigate the associations of the carotid artery IMT with the atherosclerotic risk factors.
METHODS
Ultrasound high-resolution B-mode imaging of the carotid arteries was conducted in 757 healthy subjects (385 men, 372 women) in order to determine the mean and maximal carotid artery IMT and the presence of carotid artery atherosclerotic plaques.
RESULTS
The mean carotid artery IMT values with respect to gender were 0.69+/-0.18 mm in men and 0.67+/-0.16 mm in women (NS). The mean carotid artery IMT values with respect to age in men and women were 0.57+/-0.09 mm vs 0.57+/-0.10 mm in those aged 30 to 39, 0.61+/-0.11 mm vs 0.60+/-0.10 mm in those aged 40 to 49, 0.72+/-0.21 mm vs 0.67+/-0.12 mm in those aged 50 to 59, 0.77+/-0.15 mm vs 0.71+/-0.13 mm in those aged 60 to 69 and 0.88+/-0.18 mm vs 0.76+/-0.20 mm in those aged 70 to 79, respectively. The mean carotid artery IMT was significantly greater with increasing age (p<0.001), particularly between those aged 40 to 49 and 50 to 59 (p<0.001). The maximal carotid artery IMT values for men (0.72+/-0.22 mm) were significantly greater than women (0.69+/-0.15 mm). The maximal carotid artery IMT values with respect to age in men and women were 0.60+/-0.10 mm vs 0.61+/-0.12 mm in those aged 30 to 39, 0.65+/-0.11 mm vs 0.64+/-0.11 mm in those aged 40 to 49, 0.79+/-0.29 mm vs 0.71+/-0.14 mm in those aged 50 to 59, 0.83+/-0.20 mm vs 0.77+/-0.18 mm in those aged 60 to 69 and 0.97+/-0.29 mm vs 0.80+/-0.22 mm in those aged 70 to 79. The mean carotid artery IMT was significantly greater with increasing age (p<0.001), particularly between those aged 40 to 49 and 50 to 59 (p<0.001). Age, systolic and diastolic BP, body mass index, waist/hip ratio, total cholesterol, LDL cholesterol correlated with the mean and maximal carotid artery IMT, and smoking, serum glucose, triglyceride, and HDL cholesterol levels were not correlated with the mean and maximal carotid artery IMT. Being male correlated with the maximal carotid artery IMT, but not correlated with the mean carotid artery IMT.
CONCLUSION
This study suggested reference values for the mean and maximal carotid artery IMT in healthy subjects, which can be an index for the carotid artery IMT of Koreans. Furthermore, there were significant correlations between the carotid artery IMT and the atherosclerotic risk factors in healthy subjects.