Race-ethnic differences in stroke risk factors among hospitalized patients with cerebral infarction: the Northern Manhattan Stroke Study

African-Americans have an unexplained increased incidence and mortality from stroke compared with whites, and little is known about stroke in Hispanics. To investigate cross-sectional differences in sociodemographic and stroke risk factors, we prospectively evaluated 430 patients hospitalized for acute ischemic stroke (black 35%. Hispanic 46%, white 19%) over the age of 39 from Northern Manhattan. Blacks and Hispanics were younger than whites (mean ages, blacks 70, Hispanics 67, whites 80; p < 0.001) and were more likely to have less than 12 years of education than whites. Hypertension was more prevalent in blacks and Hispanics with stroke than whites (blacks 76%, Hispanics 79%, whites 63%; p < 0.05) and was often untreated in blacks. Left ventricular hypertrophy by ECG was more frequent in blacks (blacks 20%, whites 9%; p = 0.02). History of cardiac disease (atrial fibrillation, myocardial infarction, angina, and congestive heart failure) was less prevalent in both blacks and Hispanics. Black women were significantly more obese than white women (mean Quetelet Index percent, blacks 3.9%, whites 3.6%; p < 0.05). Heavy alcohol use was more often reported by blacks and Hispanics; cigarette smoking was increased only in blacks. Moreover, blacks were less likely to have visited a physician 1 year after their stroke (blacks 85%, whites 98%; p < 0.05), and Hispanics less often lived alone compared with whites. These cross-sectional differences suggest that the burden of stroke risk factors is increased in both blacks and Hispanics with stroke. Further studies controlling for stroke risk factors are needed to establish whether race-ethnicity is an independent determinant of stroke risk.

Race-ethnicity and determinants of intracranial atherosclerotic cerebral infarction. The Northern Manhattan Stroke Study

BACKGROUND AND PURPOSE

The aim of this investigation was to determine the importance of race as a determinant of intracranial atherosclerotic stroke in a community-based stroke sample.

METHODS

Residents from northern Manhattan over age 39 years hospitalized for acute ischemic stroke (n = 438, black 35%, Hispanic 46%, white 19%) were prospectively evaluated. Index ischemic strokes were classified as atherosclerotic (17%), lacunar (30%), cardioembolic (21%), cryptogenic (31%), and other (1%). Atherosclerotic infarcts were subdivided into extracranial (9%) and intracranial (8%) atherosclerosis.

RESULTS

The proportion of extracranial atherosclerotic stroke was similar among the three race-ethnic groups, while intracranial atherosclerosis was more frequent in blacks and Hispanics. The unadjusted odds ratio for nonwhites (blacks and Hispanics combined) was 0.8 (confidence interval [CI], 0.4 to 1.8) for extracranial and 7.8 (CI, 1.04 to 57.7) for intracranial atherosclerosis. Patients with intracranial disease were significantly younger and had an increased frequency of hypercholesterolemia and insulin-dependent diabetes compared with those with nonatherosclerotic disease. The odds ratio for the association of nonwhite race-ethnicity and intracranial atherosclerosis was reduced to 5.2 (CI, 0.7 to 40) after controlling for age and to 4.4 (CI, 0.6 to 35) after controlling for age, education, insulin-dependent diabetes, and hypercholesterolemia.

CONCLUSIONS

The greater prevalence of diabetes and hypercholesterolemia among blacks and Hispanics from northern Manhattan accounted for much of the increased frequency of intracranial atherosclerotic stroke. Further control of these risk factors could reduce the frequency of this stroke subtype and minimize the disparities among different race-ethnic groups.

Predictors of mortality and recurrence after hospitalized cerebral infarction in an urban community: the Northern Manhattan Stroke Study

OBJECTIVE

To identify determinants of recurrence and mortality after ischemic stroke in a mixed-ethnic region.

BACKGROUND

The determinants of ischemic stroke outcome are not uniformly characterized and will be of increasing importance as the frequency of ischemic stroke survivors increases in our aging population.

METHODS

A cohort of 323 patients (40% black, 34% Hispanic, 26% white) with cerebral infarction from northern Manhattan over age 39 were followed for a mean of 3.3 years, with only 6% lost to follow-up. Cumulative life table risk of mortality and recurrence was calculated. Risk factors classified at the time of index ischemic stroke were selected based on univariate analyses and then entered into a Cox proportional hazards model for mortality and for recurrence.

RESULTS

The life table cumulative risk of mortality was 8% at 30 days, 22% at 1 year, and 45% at 5 years after ischemic stroke. The immediate cause of death was related to vascular disease in 60%. After age adjustment, the significant predictors of mortality were congestive heart failure (risk ratio [RR] = 2.6), admission glucose > 140 mg/dl (RR = 1.7), and presentation with either a large dominant, nondominant, or major basilar syndrome (RR = 2.0). Patients with a lacunar syndrome had a better survival (RR = 0.6). Recurrent strokes occurred in 72 patients. The life table cumulative risk of recurrence was 6% at 30 days, 12% at 1 year, and 25% at 5 years after ischemic stroke. Ethanol abuse (RR = 2.5), hypertension requiring discharge medications (RR = 1.6), and elevated blood glucose within 48 hours of index ischemic stroke (RR = 1.2 per 50 mg/dl) were the independent predictors of recurrence. Among 30-day survivors, the effect of ethanol abuse was greater (RR = 3.5), indicating its impact on late recurrence.

CONCLUSIONS

After accounting for age and presenting syndrome, initial glucose predicts stroke mortality and recurrence after ischemic stroke. This association may reflect uncontrolled and undiagnosed diabetes in our urban population. Furthermore, ethanol abuse may be a determinant of ischemic stroke recurrence. Reduction of the stroke public health burden will require targeted modification of such conditions and behaviors.