Sex Differences in the Relationship of Risk Factors to Subclinical Carotid Atherosclerosis Measured 15 Years Later

Abstract

Background and Purpose —Ultrasound measurement of carotid artery intima-media thickness (IMT) is regarded as a valid index of atherosclerosis. Determinants of IMT in cross-sectional studies have been established, but the long-term relationship between cardiovascular risk factors and subclinical atherosclerosis has not been investigated thoroughly. Methods —We included in the study 3128 middle-aged men and women in Tromsø, Norway, who in 1980 attended the baseline examination with measurements of cardiovascular risk factors and who underwent carotid ultrasonography after 15 years of follow-up. Results —Age, blood pressure, total cholesterol, HDL cholesterol, and body mass index were independent long-term predictors of IMT in both men and women. Triglyceride levels were associated with an increase in IMT in women only, while physical activity and smoking were predictors of IMT in men only. However, smoking was associated with increased risk of having atherosclerotic plaque in both men and women. There were no differences in the strength of risk factor effects on IMT in the common carotid artery and the carotid bifurcation. Conclusions —The present study indicates that established cardiovascular risk factors are independent predictors of subclinical atherosclerosis measured after 15 years of follow-up. However, there may be significant sex differences in the relationship between triglycerides, smoking, and physical activity and the risk of atherosclerosis.