Common Carotid Intima-Media Thickness and Lower Extremity Arterial Atherosclerosis

High-resolution B-mode ultrasonography of the carotid arteries is used to investigate the signs of early atherosclerotic vessel wall disease. To assess whether carotid artery findings reflect atherosclerosis elsewhere, we studied the association between common carotid intima-media thickness and lower extremity arterial atherosclerosis among the first 1000 participants of the Rotterdam Study. The Rotterdam Study is a single-center population-based prospective follow-up study of 7983 subjects, £55 years old. Baseline measurements include ultrasound imaging of intima-media thickness of the distal common carotid artery and determination of the ankle-to-arm systolic blood pressure index. Lower extremity arterial disease was defined as an ankle-arm index <0.90 in at least one leg. An increase of 0.1 mm in common carotid artery intima-media thickness was associated with an ageand sex-adjusted reduction of the ankle-arm index of 0.026 (95% confidence interval [CI]: 0.018 to 0.034). The ageand sexTo further understand the early phase of atherosclerosis, its natural history, and factors that contribute to its development, more information must be directly obtained on the arterial system in nonhospitalized subjects. Recently, it has been shown that with high-resolution B-mode ultrasonography vessel wall characteristics of the carotid arteries can be noninvasively assessed in an effective and accurate way in populations at large. This technique facilitates the evaluation of the lumen diameter, the intima-media thickness, and the presence and extent of plaques of the carotid artery and has now been applied in a number of studies. The applicability of the findings of these studies with respect to the atherosclerotic process is conditional on the extent to which noninvasively assessed common carotid intima-media thickness reflects atherosclerotic vessel wall disease in other arteries that are at high risk of atherosclerosis, such as the coronary arteries, the abdominal aorta, and arteries of the lower extremities. In other words, can increased common carotid intima-media thickness be regarded as an indicator of generalized atherosclerosis? In this study we report on the association of noninvasivefy assessed common carotid intima-media thickReceived May 20, 1994; revision accepted September 9, 1994. From the Department of Epidemiology and Biostatistics, Erasmus University Medical School, Rotterdam, the Netherlands. Correspondence to Prof D.E. Grobbee, Department of Epidemiology and Biostatistics, Erasmus University Medical School, PO Box 1738, 3000 DR Rotterdam, Netherlands. © 1994 American Heart Association, Inc. adjusted odds ratio of lower extremity arterial disease for subjects with an intima-media thickness ^0.89 mm (upper quintile) to that of subjects with an intima-media thickness <0.89 mm was 3.4 (95% CI: 2.2 to 5.2). Analysis among subjects free from symptomatic cardiovascular disease yielded a reduction in ankle-arm index per 0.1 mm increase in intima-media thickness of 0.018 (95% CI: 0.008 to 0.028) and an odds ratio for lower extremity arterial disease of 3.0 (95% CI: 1.7 to 5.1). Adjustments for differences in serum lipids, hypertension, and current smoking status only slightly attenuated the results. This study provides evidence that increased common carotid intima-media thickness reflects generalized atherosclerosis, as indicated by its association with atherosclerosis of the arteries of the lower extremities. (Arterioscter Thromb. 1994;14:1885-1891.)