Ethnic differences in stroke mortality between non-Hispanic whites, Hispanic whites, and blacks. The National Longitudinal Mortality Study

Risk of stroke in children: ethnic and gender disparities

METHODS

Using a California-wide hospital discharge database, the authors analyzed all first admissions for stroke in children 1 month through 19 years of age from 1991 through 2000. Incidence rates were estimated as the number of first hospitalizations divided by the person-years at risk; case fatality rates were based on in-hospital deaths.

RESULTS

The authors identified 2,278 first admissions for childhood stroke, yielding an annual incidence rate of 2.3 per 100,000 children (1.2 for ischemic stroke, 1.1 for hemorrhagic stroke). Compared with whites, black children were at higher risk of stroke (for ischemic stroke, relative risk [RR] 2.59, 95% CI 2.17 to 3.09, p < 0.0001; subarachnoid hemorrhage [SAH], RR 1.59, CI 1.06 to 2.33, p = 0.02; intracerebral hemorrhage [ICH], RR 1.66, CI 1.23 to 2.13, p = 0.0001). Hispanics, however, had a lower risk of ischemic stroke (RR 0.70, CI 0.60 to 0.82, p < 0.0001) and ICH (RR 0.77, CI 0.64 to 0.93, p = 0.0004), whereas Asians had similar risks as whites. Boys were at higher risk for all stroke types than girls (ischemic stroke, RR 1.25, CI 1.11 to 1.40, p = 0.0002; SAH, RR 1.24, CI 1.00 to 1.53, p = 0.047; ICH, RR 1.34, CI 1.16 to 1.56, p = 0.0001). After eliminating cases with coexisting sickle cell disease, excess stroke risk persisted in blacks; after elimination of trauma, excess stroke risk persisted in boys. Case fatality rates were similar among different ethnic groups. Compared with girls, boys had a higher case fatality rate for ischemic stroke (17 vs 12%; p = 0.002) but not for ICH or SAH.

CONCLUSIONS

Rates of hospitalization for stroke are higher among black children and boys; sickle cell disease and trauma do not fully account for these findings.

Stroke risk factor profiles in African American women: an interim report from the African-American Antiplatelet Stroke Prevention Study

BACKGROUND AND PURPOSE

If sex differences in stroke risk factor profiles exist among African Americans in the United States, prevention strategies will need to reflect those differences. African Americans and women have been underrepresented in stroke prevention studies. The purpose of this study was to determine whether medical and lifestyle factors differ among women and men who have enrolled in the African-American Antiplatelet Stroke Prevention Study (AAASPS).

METHODS

We performed a planned exploratory analysis of differences in baseline characteristics and risk factors between women and men enrolled in AAASPS, a double-blind, randomized, multicenter, controlled trial. Frequencies of vascular risk factors and related conditions, medical therapies, stroke subtypes, and vascular territories were compared between women and men by 1-way ANOVA and Fisher's exact test where appropriate.

RESULTS

A total of 1087 African American patients (574 women, 513 men) enrolled between December 1995 and June 1999. Women had higher rates of hypertension, diabetes, family history of stroke, and no reported leisure exercise. Men had higher rates of smoking and heavy alcohol use. Few differences were noted in proportions of stroke subtype or proportions receiving preventive therapy.

CONCLUSIONS

AAASPS represents the largest enrollment of African American women in a recurrent stroke prevention study. Our data suggest that African American women in a clinical trial differ from men in the frequency of key vascular risk factors. Although limited, these data provide an important first characterization of sex differences in African Americans with stroke.

Incidence and case fatality rates of stroke subtypes in a multiethnic population: the South London Stroke Register

OBJECTIVE

To identify sociodemographic differences in the incidence of the subtypes of first ever stroke in a multiethnic population.

METHODS

A prospective community stroke register (1995-8) was developed using multiple notification sources and pathological and clinical classifications of stroke. Standardisation of rates was to European and World populations and adjusted for age, sex and socioeconomic status in multivariate analyses. A multiethnic population of 234 533 in south London, of whom 21% are black was studied.

RESULTS

A total of 1254 cases were registered. The average age of stroke was 71.7 years with black patients being 11.3 years younger than white patients (p<0.0001). The incidence rate/1000 population was 1.33 (crude) (95% CI 1.26 to 1.41), 1.28 (European adjusted) (95% CI 1.2 to 1.35) with a 2.18 (95% CI 1.86 to 2.56) (p<0.0001) age and sex adjusted incidence rate ratio in the black population. Radiological diagnosis was confirmatory in 1107 (88.3%) with 862 (68.7%) infarction, 168 (13.4%) primary intracerebral haemorrhage, and 77 (6.2%) subarachnoid haemorrhage. Of the cerebral infarction cases 189 (21.9%) were total anterior circulatory, 250 (29%) partial anterior, 141 (16.4%) posterior (POCI) and 282 (32.7%) lacunar infarcts. The black group had a significantly higher incidence of all subtypes of stroke except for POCI and unclassified strokes. The incidence rate ratio (IRR) for men compared with women was 1.34 (95% confidence interval (95% CI) 1.19 to 1.50; p<0.001). The IRR for manual versus non-manual occupations in those aged 35-64 years was 1.64 (95%CI 1.22 to 2.23; p<0.0001). There was a borderline significant increase in adjusted survival at 6 months in the black group 95% (CI 0.61 to 1.03, p=0.078) with a hazard ratio of 0.79 after adjustment and stratification.

CONCLUSIONS

Although the black population is at increased risk of stroke and most subtypes of stroke, this is not translated into significant differences in survival. Hence black/white differences in mortality are mainly driven by incidence of stroke. There are striking demographic inequalities in the risk of stroke in this multiethnic inner city population that need to be tackled through interagency working. Although the reasons for the increased risk in the black population are unclear, demographic factors such as socioeconomic status do seem to play a significant independent part.

Race, socioeconomic status, and cause-specific mortality

PURPOSE

Life expectancy for black Americans is five to eight years less than for Whites. The socioeconomic status (SES) of Blacks is also less than for Whites, and SES is associated with early mortality. This paper estimates the proportion of the racial difference in mortality attributable to SES by specific causes of death.

METHODS

Data on 453,384 individuals in the National Longitudinal Mortality Study were used to estimate the hazard ratio associated with black race, with and without adjustment for income and education (measures of SES), in 38 strata defined by cause of death and age.

RESULTS

For women, SES accounted for much (37-67%) of the black excess mortality for accidents, ischemic heart disease (ages 35-54), diabetes, and homicide; but not for hypertension, infections, and stomach cancers (11-17%). For men, SES accounted for much of the excess risk (30-55%) for accidents, lung cancer, stomach cancer, stroke, and homicide; but not for prostate cancer, pulmonary diseases, hypertension, and cardiomyopathy (0-17%).

CONCLUSIONS

These results confirm those specific causes of death likely to underlie the overall excess mortality of Blacks, and identify those causes where SES may play a large role.

Stroke in Hispanic Americans

The Hispanic American population is the fastest growing minority group with increasing representation among the older age strata. Current ethnic-specific cerebrovascular disease data regarding stroke outcomes and risk factor status reveal significant differences compared with other race/ethnic groups. The authors discuss the literature on stroke incidence and mortality among Hispanic populations. Traditional risk factors, access to care and stroke mechanism differences are also discussed. Advances in Hispanic American specific stroke prevention and treatment efforts demand further investigation to better define Hispanic American stroke prevention and acute treatment strategies.

Stroke risk factors

Despite advances in the treatment of acute cerebral infarction, the most effective method of reducing stroke morbidity and mortality is the identification and modification of stroke risk factors. Modifiable stroke risk factors include hypertension, atrial fibrillation, hypercholesterolemia, cigarette smoking, hyperhomocystinemia, and carotid stenosis. Improved identification of individuals at increased stroke risk due to these factors can reduce individual risk and the cost to society of the consequences of stroke.

Efficacy of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors for prevention of stroke

OBJECTIVE

To determine if 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are effective in preventing fatal and nonfatal strokes in patients at increased risk of coronary artery disease.

DESIGN

Meta-analysis of randomized controlled trials. Clinical trials were identified by a computerized search of MEDLINE (1983 to June 1996), by an assessment of the bibliographies of published studies, meta-analyses and reviews, and by contacting pharmaceutical companies that manufacture statins. Trials were included in the analysis if their patients were randomly allocated to a statin or placebo group, and reported data on stroke events. Thirteen of 28 clinical trials were selected for review. Data were extracted for details of study design, patient characteristics, interventions, duration of therapy, cholesterol measurements, and the number of fatal and nonfatal stroke events in each arm of therapy. Missing data on stroke events were obtained by contacting the investigators of the clinical trials.

MAIN RESULTS

Among 19,921 randomized patients, the rate of total stroke in the placebo group was 2.38% (90% nonfatal and 10% fatal). In contrast, patients who received statins had a 1.67% stroke rate. Using an exact stratified analysis, the pooled odds ratio (OR) for total stroke was 0.70 (95% confidence interval [CI] 0.57, 0.86; p =.0005). The pooled OR for nonfatal stroke was 0.64 (95% CI 0.51, 0.79; p =.00001), and the pooled OR for fatal stroke was 1.25 (95% CI 0.71, 2.24; p =.4973). In separate analyses, reductions in total and nonfatal stroke risk were found to be significant only for trials of secondary coronary disease prevention. Regression analysis showed no statistical association between the magnitude of cholesterol reduction and the relative risk for any stroke outcome.

CONCLUSIONS

The available evidence clearly shows that HMG-CoA reductase inhibitors reduce the morbidity associated with strokes in patients at increased risk of cardiac events. Data from 13 placebo-controlled trials suggest that on average one stroke is prevented for every 143 patients treated with statins over a 4-year period.

Definition of race and ethnicity in older people in Medicare and Medicaid

BACKGROUND

Race and ethnicity are important predictors of health care access and outcomes, but quality of their documentation in the healthcare system is often problematic.

OBJECTIVES

To study the agreement between Medicare and Medicaid descriptions of race and ethnicity in older beneficiaries.

DESIGN

Quasiexperimental design in a natural practice setting.

SETTING

New Jersey.

PARTICIPANTS

153,241 dually enrolled participants in Medicare and Medicaid.

MEASUREMENTS

Agreement rates between administrative databases on recipients' race and ethnicity.

RESULTS

Agreement between Medicare and Medicaid on the recipients' race and ethnicity was modest (kappa = .58; 95% CI, .57-.58) for men and women alike and across different age groups. Depending on whether Medicare or Medicaid was used as the reference standard, the relative agreement rates for race and ethnic group assignments varied. For example, using Medicare as the reference, the relative agreement rate was 84% for whites, 74% for blacks, 61% for others, 23% for Hispanics, and only 5% for Asians. Using Medicaid as the reference, a different pattern emerged. However, such gradients of agreement rates across racial groups were observed in both programs. Medicare and Medicaid reported different percentages of all race and ethnicity groups, with Medicaid reporting greater proportions of White and Black beneficiaries, and Medicare reporting greater proportions of Hispanic, Asian, and Other groups.

CONCLUSIONS

Depiction of race and ethnicity data in large government health insurance programs is approximate at best and often contradictory from one program to another. This can impede efforts to study the relationship between these important characteristics and health care utilization and outcomes.

The 2 Gene Coding Sequence T807/A873 of the Platelet Collagen Receptor Integrin 2β1 Might Be a Genetic Risk Factor for the Development of Stroke in Younger Patients

The polymorphisms C807T and G873A of the platelet integrin 2β1 (collagen receptor glycoprotein [GP] Ia-IIa) are linked to the expression density of this receptor. The GPIa T807/A873 allele causes a higher receptor expression, enhancing platelet binding to collagen. This might present a genetic predisposition for the development of thromboembolic complications. In this case-control study, the genotypes of the GPIa C807T polymorphism and presence of conventional risk factors (hypertension, diabetes mellitus, and smoking) were compared in stroke patients and patients without cerebrovascular disease (non-CVD patients) ≤50 years of age (n = 45 and 41, respectively) and in stroke patients and non-CVD patients more than 50 years of age (n = 182 and 129, respectively. In patients ≤50 years of age, the T807 allele was the only overrepresented variable (P = .023; odds ratio, 3.02; 95% confidence interval, 1.20 to 7.61) and an independent risk factor, whereas the presence of conventional risk factors was similar between stroke patients ≤50 years of age and non-CVD patients ≤50 years of age. Large epidemiological studies should prove whether the platelet collagen receptor GPIa-IIa T807 allele is an independent risk factor for the development of stroke in younger patients.

The 2 Gene Coding Sequence T807/A873 of the Platelet Collagen Receptor Integrin 2β1 Might Be a Genetic Risk Factor for the Development of Stroke in Younger Patients

The polymorphisms C807T and G873A of the platelet integrin 2β1 (collagen receptor glycoprotein [GP] Ia-IIa) are linked to the expression density of this receptor. The GPIa T807/A873 allele causes a higher receptor expression, enhancing platelet binding to collagen. This might present a genetic predisposition for the development of thromboembolic complications. In this case-control study, the genotypes of the GPIa C807T polymorphism and presence of conventional risk factors (hypertension, diabetes mellitus, and smoking) were compared in stroke patients and patients without cerebrovascular disease (non-CVD patients) ≤50 years of age (n = 45 and 41, respectively) and in stroke patients and non-CVD patients more than 50 years of age (n = 182 and 129, respectively. In patients ≤50 years of age, the T807 allele was the only overrepresented variable (P = .023; odds ratio, 3.02; 95% confidence interval, 1.20 to 7.61) and an independent risk factor, whereas the presence of conventional risk factors was similar between stroke patients ≤50 years of age and non-CVD patients ≤50 years of age. Large epidemiological studies should prove whether the platelet collagen receptor GPIa-IIa T807 allele is an independent risk factor for the development of stroke in younger patients.

Why do we have a stroke belt in the southeastern United States? A review of unlikely and uninvestigated potential causes

Although there is widespread recognition of a region with high stroke mortality in the southeastern United States that has persisted over the past 50 years (ie, the "stroke belt"), there is little agreement as to its underlying cause(s). Herein, we review data supporting 10 potential causes for the stroke belt, and assess: (1) the likelihood that each is the contributing factor to the excess mortality, and (2) areas of investigation where data are lacking and that require additional research efforts.

A triethnic comparison of intracerebral hemorrhage mortality in Texas

Intracerebral hemorrhage (ICH) is a significant cause of stroke death. Little is known about the relative risk of Hispanic Americans (HAs), African Americans (AAs), and non-Hispanic whites (NHWs) for ICH mortality. Based on the high prevalence of hypertension in AAs and the low prevalence of hypertension in HAs, we expected AAs to have the highest ICH mortality rates and HAs the lowest. Race/ethnic age-specific ICH mortality rates were calculated from Texas vital statistics for the years 1980 through 1995. Rate ratios (RRs) are reported with NHWs as the referent group. There were 15,042 deaths due to ICH in Texas during this time. In the 45- to 59-year age group, AAs had an RR of 4. The RR for HAs was 1.9. In the 60- to 74-year age range, AAs had an RR of 1.7 and HAs had an RR of 1.3. In the 75+ age group, the rates were similar among all three race/ethnic groups. We conclude that there is a significant interaction of age and race/ethnicity for ICH. At younger ages, AAs and HAs have the highest ICH mortality rates. Access to care and socioeconomic status may play a role in the unexpectedly high ICH mortality rates in HAs.

Region of birth and mortality from circulatory diseases among black Americans

OBJECTIVES

This study examines the relationship between birth-place and mortality from circulatory diseases among American Blacks.

METHODS

All Black deaths from circulatory diseases (International Classification of Diseases, 9th Revision. codes 390 through 459) were extracted from the National Center for Health Statistics mortality detail files for 1979 through 1991. Age-specific and age-adjusted mortality rates with 95% confidence intervals were calculated for males and females for combinations of five regions of residence at birth and four regions of residence at death.

RESULTS

Males had higher mortality rates from circulatory diseases than females in every regional combination of birthplace and residence at death. For both genders, the highest rates were for those who were born in the South but died in the Midwest; the lowest rates were for those who were born in the West but died in the South. Excess mortality for both Southern-born males and females begins at ages 25 through 44.

CONCLUSIONS

There is a region-of-birth component that affects mortality risk from circulatory diseases regardless of gender or residence at time of death. We must examine how early life experiences affect the development of circulatory disorders.

The stroke belt consortium

The "Stroke Belt" describes a region of the southeastern United States with a high incidence of stroke and mortality due to stroke. In an effort to address the problem of stroke in this region, we have formed the Stroke Belt Consortium (SBC). This report describes the formation and functions of the SBC. The SBC is a unique organization with representatives from many areas, including health care, government, nonprofit organizations, the pharmaceutical industry, minority groups, educational groups, and managed care. The goals of the consortium are to advance public and professional education about stroke in the Stroke Belt, with a special emphasis on the populations in that region. The first meeting of the consortium was held in November 1994. Many helpful and innovative ideas and initiatives were generated at the first SBC meeting. These included improved techniques for professional education, the development of a mass media campaign for public education, screening of college students for stroke risk factors, and using fast-food restaurants and sporting events as venues to promote stroke education. This type of organized effort may produce cost-effective programs and initiatives, particularly for largescale educational efforts, that will enhance the prevention and treatment of stroke patients. If successful in the Stroke Belt, similar organizations can be formed in other regions of the nation to address specific issues related to stroke prevention, education, and treatment.

Clinical epidemiology of stroke

The effect of stroke as a major health issue in the United States is well established. Well-designed epidemiologic studies have contributed important information about the natural history of stroke and its associated risk factors. These cerebrovascular profiles have provided the foundation for many of the current ischemic stroke trials, but the cause and prevention of the hemorrhagic subtypes remain elusive.