Bernadette Boden-Albala

Testing the validity of the lacunar hypothesis: The northern Manhattan stroke study experience

Backgrouncd/Objective Few studies have attempted to validate the “lacunar hypothesis.” The accuracy of identifying lacunar and other nonlacunar mechanisms of infarction will be increasingly important in evaluating potential stroke treatments. The aim of this study was to determine the value of lacunar syndromes in predicting radiologic lacunes and the value of clinicoradiologic lacunes in predicting “lacunar infarction” as final stroke mechanism. Methods From 1990 to 1994, 591 patients with cerebral infarction, who were from northern Manhattan and over the age of 39, were prospectively examined. Data were collected on the admitting clinical syndrome (lacunar or nonlacunar) and brain imaging findings. Lacunar syndromes were categorized as pure motor hemiparesis (PMH), pure sensory syndrome (PSS), sensorimotor syndrome (SMS), ataxic-hemiparesis (A-H), and other lacunar syndromes. Brain imaging findings were classified as radiologic lacune or nonlacune. Positive predictive values, sensitivities, and specificities of lacunar syndromes for identifying radiologic lacunes were calculated. The final mechanism of infarction was determined after review of all the diagnostic tests and compared among the lacunar groups. Results Lacunar syndromes occurred in 225 cases. PMH was the most common lacunar syndrome, accounting for 45%, SMS 20%, A-H 18%, and PSS 7%. Lacunar syndromes had an overall positive predictive value (PPV) of 87% for detecting radiologic lacune: PSS loo%, A-H 95%, SMS 87%, and PMH 79%. Among the 195 patients who presented with a lacunar syndrome and had this condition confirmed radiologically, 147 were classified as having a final diagnosis of lacunar mechanism of infarction (PPV = 75%). Atherosclerosis accounted for 17 (9%), cardioembolism 10 (5%), cryptogenic 17 (9%), and other unusual causes 4 (2%). Conclusion While lacunar syndromes, especially PSS and A-H, are highly predictive of lacune, in about one in four patients presenting with lacunar syndromes confirmed radiologically the condition is associated with nonlacunar mechanisms of infarction. Noninvasive neurovascular and cardiac evaluations are still warranted even among patients with lacunes.

Race-Ethnicity and Determinants of Carotid Atherosclerosis in a Multiethnic Population: The Northern Manhattan Stroke Study

BACKGROUND AND PURPOSEnRisk 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.nnnMETHODSnAs part of the Northern Manhattan Stroke Study, 526 stroke-free community residents (aged > or = 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.nnnRESULTSnMean 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.nnnCONCLUSIONSnAtherosclerotic 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.

Lipid and lipoprotein levels remain stable in acute ischemic stroke: the Northern Manhattan Stroke Study

Serum lipoproteins including lipoprotein(a), Lp(a), are emerging as possible biological markers for cerebrovascular disease. Existing data on Lp(a) and serum lipids levels following acute ischemic stroke (AIS) are however equivocal. To determine whether serum Lp(a) and other lipid levels obtained within 24 h of acute ischemic stroke onset changed over the ensuing 4 weeks and whether these levels are related to an acute phase response, acquired nutritional deficiency, and neurovascular data, we conducted repeated measurement analyses among 19 subjects (mean age 65.0 +/- 12.1 years; 32% women) presenting with AIS (evaluated within 9.7 +/- 12.7 h). Eleven of the subjects had a moderate-to-severe stroke, defined by NIH stroke severity scale, and seven patients had a large cerebral infarction. Seven serial measurements of Lp(a), total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, and other lipoproteins, major acute phase reactants and albumin levels were collected for each subject over 4 weeks. The mean initial levels, (mg/dl), of total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, Lp(a), apolipoproteins A-I and B were: 225 +/- 57.6, 154 +/- 56.0, 40 +/- 10.4, 181 +/- 93.7, 52 +/- 28.6, 130 +/- 24.6, and 141 +/- 46.1, respectively. There were no significant changes in mean serum lipid, apolipoprotein or Lp(a) levels over the 4-week study period, analyzed by a random effects model to test for time trend. In addition, there were no significant changes in established acute phase or nutritional markers (C-reactive protein, alpha 1-glycoprotein, haptoglobin or serum albumin). Our findings suggest that serum lipid, apolipoprotein and Lp(a) levels remain stable following AIS, consistent with the absence of acute phase response or nutritional deficiency.

Validity of Telephone Interview Data for Vascular Disease Risk Factors in a Racially Mixed Urban Community: The Northern Manhattan Stroke Study

The aims of our study were to assess the validity and reliability of a telephone survey instrument designed to measure vascular disease risk factors and to assess whether these measurements were influenced by age, gender, race/ethnicity, or other sociodemographic variables. Subjects were sampled and interviewed using random digit dialing methodology from the multiethnic community of northern Manhattan. For the validity study, 261 consecutive subjects were clinically assessed in-person within 60 days of the telephone interview. A retest reliability study of the telephone interview was conducted in 92 randomly selected subjects within 30 days of the initial interview. The telephone interview instrument had a sensitivity of more than 55% and a specificity of 74% or greater for various vascular disease risk factors. Sensitivity, specificity, and positive predictive value did not vary significantly or systematically among whites, blacks, and Hispanics, but subjects with access to health care were more likely to provide valid data. The reliability substudy indicated a good reliability for the telephone interview. These results support the validity of telephone interviews for estimating the prevalence of vascular risk factors in urban populations.

Social Readjustment and Ischemic Stroke: Lack of an Association in a Multiethnic Population

Clinical experience has suggested that stressful life events and ongoing stressful illness, collectively termed ‘social readjustment’, may precipitate stroke. We investigated the association between a simple in-office evaluation of such stressors and stroke in an urban, multiethnic study population. Cases were patients from the Northern Manhattan Stroke Study with first ischemic stroke; controls were derived through random digit dialing with n:m matching for age, gender, and race-ethnicity. Social readjustment was measured through in-person interview using Amster and Krauss’ Geriatric Social Readjustment Rating Scale (GSRRS), a one-time, 35-item, checklist type weighted questionnaire of stressful life events occurring in the previous 6 months. Conditional logistic regression was used to analyze the GSRRS and its quartiles as well as stressful events subgroups, adjusting for education, hypertension, cardiac disease, diabetes, and number of weekly visits as a measure of socialization. Six hundred and fifty-five cases of ischemic stroke and 1,087 controls were utilized. The mean age of the cases was 69.8 years, with 55.4% women, 51.0% Hispanics, 28.4% blacks, and 19.1% whites. GSRRS scores ranged from 0 to 812; the mean score was 205.5 for the cases and 206.2 for the controls. The analysis showed no association between stroke and a 20-point increase on the GSRRS (OR = 1.01, 95% CI = 0.99–1.01). There was also no effect for the second, third or highest versus lowest quartile. No association was found in age, gender or race-ethnic subgroups, or when analyzing negative events, severely threatening events, or ongoing stressful illnesses separately. While this study does not preclude social readjustment as a stroke risk factor, it suggests that the one-time assessment often done in the medical office setting has little relevance for stroke prevention planning.

The protective effect of moderate alcohol consumption on ischemic stroke

CONTEXTnModerate alcohol consumption has been shown to be protective for coronary heart disease, but the relationship between moderate alcohol consumption and ischemic stroke is more controversial.nnnOBJECTIVEnTo determine the association between alcohol consumption and risk of ischemic stroke.nnnDESIGNnPopulation-based case-control study conducted between July 1993 and June 1997.nnnSETTINGnMultiethnic population in northern Manhattan, New York, NY, aged 40 years or older.nnnPATIENTS AND OTHER PARTICIPANTSnCases (n = 677) had first ischemic stroke and were matched to community controls (n = 1139) derived through random digit dialing by age, sex, and race/ethnicity. Mean +/- SD age of cases was 70.0+/-12.7 years; 55.8% were women; 19.5% were white, 28.4% black, and 50.7% Hispanic.nnnMAIN OUTCOME MEASUREnFirst ischemic stroke (fatal or nonfatal).nnnRESULTSnModerate alcohol consumption, up to 2 drinks per day, was significantly protective for ischemic stroke after adjustment for cardiac disease, hypertension, diabetes, current smoking, body mass index, and education (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.39-0.67). This protective effect of alcohol consumption was detected in both younger and older groups, in men and women, and in whites, blacks, and Hispanics. In a quadratic model of stroke risk, increased risk of ischemic stroke was statistically significant among those consuming 7 or more drinks per day (OR, 2.96; 95% CI, 1.05-8.29).nnnCONCLUSIONSnModerate alcohol consumption was independently associated with a decreased risk of ischemic stroke in our elderly, multiethnic, urban subjects, while heavy alcohol consumption had deleterious effects. Our data support the National Stroke Association Stroke Prevention Guidelines regarding the beneficial effects of moderate alcohol consumption.