Carotid plaque, aging, and risk factors. A study of 457 subjects.

BACKGROUND AND PURPOSE The aim of this study was to assess the prevalence of extracranial carotid artery atherosclerosis and its relation to principal cardiovascular risk factors at different ages in a sample of the general population. METHODS B-mode ultrasonography was used to investigate the carotid district in 457 subjects (231 men and 226 women; mean age, 55.4 +/- 18.7 years; range, 18 to 97 years) in the metropolitan area. The ultrasonographic findings were then related to risk factors. RESULTS Carotid plaques were found in 178 subjects (38.9%). The prevalence of atherosclerosis, number of plaques, and severity of stenosis were observed to increase with age. Age (P < .0001), cigarette smoking (P < .0001), male sex (P < .001), total cholesterol (P < .05), and, inversely, the ratio of high-density lipoprotein cholesterol to total cholesterol (P < .05) were found to be independently associated with carotid atherosclerosis. Stratified analysis by sex and age showed effect modifications by age on cigarette smoking, total cholesterol, and the ratio of high-density lipoprotein cholesterol to total cholesterol. After multivariate analysis including interaction terms, cigarette smoking and cholesterol levels were not longer found to be associated with carotid atherosclerosis in elderly subjects. Age (P < .01), total cholesterol (P < .05), and diabetes (P < .05) were positively related to the severity of vascular narrowing. CONCLUSIONS There is a high prevalence of asymptomatic carotid atherosclerosis in the general population, particularly among the very old. The association between risk factors and carotid atherosclerosis is less pronounced in the elderly than in younger subjects.