Race-ethnicity and determinants of carotid atherosclerosis in a multiethnic population: The Northern Manhattan Stroke Study

Background and Purpose: Risk factors for carotid atherosclerosis have been studied in white populations but infrequently in multiethnic cohorts. The aim of this study was to determine the importance of race-ethnicity and other factors associated with carotid atherosclerosis in a mixed population of Hispanics, blacks, and whites. Methods: As part of the Northern Manhattan Stroke Study, 526 stroke-free community residents (aged ≤40 years; 41% men, 59% women; 46% Hispanic, 31% black, 23% white) were recruited through random- digit dialing and had vascular risk factor evaluations. Maximum internal carotid artery plaque thickness (MICPT) was measured with B-mode ultrasound. The frequency distribution of MICPT was examined in the three race-ethnic groups, and multivariate regression was performed to identify factors that were independently associated with MICPT. Results: Mean MICPT in the entire sample was 1.5±1.4 mm, increased directly with age, and was greater in whites and blacks than Hispanics. Other independent determinants of MICPT included smoking, glucose, LDL cholesterol, and hypertension. After we controlled for these covariates, Hispanic (versus non-Hispanic) race- ethnicity was still an independent determinant of less carotid plaque. There was a significant interaction between race-ethnicity and LDL cholesterol, with a greater effect of increasing LDL cholesterol among Hispanics. Conclusions: Atherosclerotic risk factors were predictive of MICPT in this mixed-ethnic cohort. Hispanics had significantly less carotid plaque after adjustment for other known risk factors, but they also had a greater impact of increasing LDL cholesterol.