Disparities In Stroke Incidence Research Articles

Abstract 14: Associations Between Measures of Structural Racism and Acute Ischemic Stroke Incidence in the US

Introduction: Racial differences in socioeconomic characteristics are believed to be secondary to structural racism. While socioeconomic factors explain some of the racial disparity in stroke incidence at an individual level, little is known about the association between societal-level structural racism and the incidence of acute ischemic stroke (AIS). Methods: We conducted a national cross-sectional analysis of 71,078,619 adults aged >65 years enrolled in Medicare from January 1, 2016 to December 31, 2019. The primary exposure was a county-level composite structural racism score that was calculated from constituent measures of structural racism: segregation indices (delta index, dissimilarity index, isolation index), Gini index, housing discrimination, educational attainment ratio, employment ratio, income ratio. The primary outcome was AIS incidence. Results: The composite structural racism score identified significant geographic variation in structural racism across the U.S. (mean 0.818, SD 2.874, IQR 3.02). Among 844,406 Medicare beneficiaries with incident AIS, Black individuals had a 19% increased hazard of AIS compared to White individuals (HR 1.19, 95% CI 1.14-1.25, p<0.0001). Increasing segregation conferred increased incidence of AIS for both Black and White populations. Each standard deviation increase in the composite structural racism score was associated with an 18% increased incidence in AIS (HR 1.18, 95% CI 1.12-1.24) in the total population. This association interacted with race (p=0.03), with a greater magnitude of association for White (HR 1.19, 95% CI 1.13-1.25, p<0.0001) versus Black (HR 1.09 ,95% CI 1.03-1.16, p=0.0073) individuals. Conclusions: There is significant geographic variation in structural racism at the county level across the US, and increasing levels of structural racism are associated with increased incidence of AIS, regardless of race.

Racial disparities in stroke incidence in the Women's Health Initiative: Exploring biological, behavioral, psychosocial, and social risk factors

Background– Disparities in incident stroke risk among women by race and ethnicity persist. Few studies report the distribution and association of stroke risk factors by age group among a diverse sample of women. Methods– Data from the Women's Health Initiative (WHI) Observational Study collected between 1993 and 2010 were used to calculate cumulative stroke incidence and incidence rates among non-Hispanic African American (NHAA), non-Hispanic white (NHW), and Hispanic white or African American (HWAA) women by age group in participants aged ≥50 years at baseline (N = 77,247). Hazard ratios (HRs) and 95% CIs for biological, behavioral, psychosocial, and socioeconomic factors overall and by race or ethnicity were estimated using sequential Cox proportional hazard regression models. Results– Average follow-up time was 11.52 (SD, 3.48) years. The incident stroke rate was higher among NHAA (306 per 100,000 person-years) compared to NHW (279/100,000py) and HWAA women (147/100,000py) overall and in each age group. The disparity was largest at ages >75 years. The association between stroke risk factors (e.g., smoking, BMI, physical activity) and incident stroke varied across race and ethnicity groups. Higher social support was significantly associated with decreased stroke risk overall (HR:0.84, 95% CI, 0.76, 0.93); the degree of protection varied across race and ethnicity groups. Socioeconomic factors did not contribute additional stroke risk beyond risk conferred by traditional and psychosocial factors. Conclusions– The distribution and association of stroke risk factors differed between NHAA and NHW women. There is a clear need for stroke prevention strategies that address factors driving racial disparities in stroke risk.

Improving Stroke Risk Factor Management Focusing on Health Disparities and Knowledge Gaps.

Stroke is a leading cause of death and disability in the United States and worldwide, necessitating comprehensive efforts to optimize stroke risk factor management. Health disparities in stroke incidence, prevalence, and risk factor management persist among various race/ethnic, geographic, and socioeconomic populations and negatively impact stroke outcomes. This review highlights existing literature and guidelines for stroke risk factor management, emphasizing health disparities among certain populations. Moreover, stroke risk factors for special groups, including the young, the very elderly, and pregnant/peripartum women are outlined. Strategies for stroke risk factor improvement at every level of the health care system are discussed, from the individual patient to providers, health care systems, and policymakers. Improving stroke risk factor management in the context of the social determinants of health, and with the goal of eliminating inequities and disparities in stroke prevention strategies, are critical steps to reducing the burden of stroke and equitably improving public health.

Perceived Interpersonal Racism and Incident Stroke Among US Black Women

Black individuals in the US experience stroke and stroke-related mortality at younger ages and more frequently than other racial groups. Studies examining the prospective association of interpersonal racism with stroke are lacking. To examine the association of perceived interpersonal racism with incident stroke among US Black women. The Black Women's Health Study, a prospective cohort study of 59 000 Black women from across the US, assessed the longitudinal association between perceived interpersonal racism and stroke incidence. Stroke-free participants were followed up from 1997 until onset of stroke, death, loss to follow-up, or the end of the study period (December 31, 2019). Cox models were used to estimate hazard ratios (HRs) and 95% CIs, adjusting for major confounders, including education, neighborhood socioeconomic environment, and cardiometabolic factors. Data analysis was performed from March 2021 until December 2022. On a questionnaire completed in 1997, participants reported experiences of racism in everyday life and when dealing with situations that involved employment, housing, and interactions with police. Strokes were identified through self-report on biennial questionnaires, medical records adjudication, and linkage with the National Death Index. In 1997, 48 375 Black women (mean [SD] age, 41 [10] years) provided information on perceived interpersonal racism and were free of cardiovascular disease and cancer. During the 22 years of follow-up, 1664 incident stroke cases were identified; among them, 550 were definite cases confirmed by neurologist review and/or National Death Index linkage. Multivariable HRs for reported experiences of racism in all 3 domains of employment, housing, and interactions with police vs no such experiences were 1.38 (95% CI, 1.14-1.67), a 38% increase, for all incident cases and 1.37 (95% CI, 1.00-1.88) for definite cases. For comparisons of women in the highest quartile of everyday interpersonal racism score vs women in the lowest quartile, multivariable HRs were 1.14 (95% CI, 0.97-1.35) for analyses that included all incident stroke and 1.09 (95% CI, 0.83-1.45) for analyses that included definite cases only. In this study, Black women who reported experiences of interpersonal racism in situations involving employment, housing, and interactions with police appeared to have an increased risk of stroke, even after accounting for demographic and vascular risk factors, suggesting that the high burden of racism experienced by Black US women may contribute to racial disparities in stroke incidence.

Disparities in Stroke Incidence Over Time by Sex and Age in Latin America and the Caribbean Region 1997 to 2021: A Systematic Review and Meta-Analysis.

Background High-income country studies show unfavorable trends in stroke incidence (SI) in younger populations. We aimed to estimate temporal change in SI disaggregated by age and sex in Latin America and the Caribbean region. Methods and Results A search strategy was used in MEDLINE, WOS, and LILACS databases from 1997 to 2021, including prospective population-based observational studies with first-ever stroke incidence in Latin America. Reports without data broken down by age and sex were excluded. Risk of bias was assessed with The Joanna Briggs Institute's guide. The main outcomes were incidence rate ratio and relative temporal trend ratio of SI, comparing time periods before 2010 with after 2010. Pooled relative temporal trend ratios considering only studies with 2 periods in the same population were calculated by random-effects meta-analysis. Meta-regression analysis was used to evaluate incidence rate determinants. From 9242 records identified, 6 studies were selected including 4483 first-ever stroke in 4 101 084 individuals. Crude incidence rate ratio in younger subjects (<55 years) comparing before 2010:after 2010 periods showed an increase in SI in the past decade (incidence rate ratio, 1.37 [95% CI, 1.23-1.50]), in contrast to a decrease in older people during the same period (incidence rate ratio, 0.83 [95% CI, 0.76-0.89]). Overall relative temporal trend ratio (<55:≥55 years) was 1.65 (95 CI%, 1.50-1.80), with higher increase in young women (pooled relative temporal trend ratio, 3.08 [95% CI, 1.18-4.97]; P for heterogeneity <0.001). Conclusions An unfavorable change in SI in young people, especially in women, was detected in population-based studies in the past decade in Latin America and the Caribbean. Further investigation of the explanatory variables is required to ameliorate stroke prevention and inform local decision-makers. Registration URL: https://www.crd.york.ac.uk/prospero/ Identifier: CRD42022332563.

Racial and Ethnic Diversity in Endovascular Thrombectomy Trials

The burden of acute ischemic stroke varies among racial and ethnic groups. Black adults face a higher incidence of stroke as well as higher rates of mortality. Thrombolytic therapy is under‐utilized in Black adults, and recent data show that endovascular thrombectomy is also under‐utilized for Black and Hispanic adults in the United States. Despite federal initiatives designed to promote the representation of diverse racial and ethnic groups in academic research, Black and Hispanic adults continue to be underrepresented in clinical trials conducted in the United States. Globally, the lack of standardization regarding race and ethnicity reporting makes it challenging to determine the overall diversity of trial enrollment. In this topical review, we provide an overview of racial and ethnic disparities in stroke incidence and clinical care with a focus on endovascular thrombectomy and follow this with a description of diversity reporting in endovascular thrombectomy trials. We conclude with opportunities for and barriers to increasing racial and ethnic diversity in endovascular thrombectomy trials.

Abstract 140: The Incidence Of Stroke In Indigenous Populations Of Countries With A Very High Human Development Index: A Systematic Review.

Introduction: Despite known socioeconomic and health disparities affecting Indigenous populations in developed countries, stroke incidence data are sparse. With Indigenous Advisory Board oversight, we undertook a systematic review to compare Indigenous with non-Indigenous stroke incidence rates in countries with a very high Human Development Index (HDI). Methods: We identified population-based stroke incidence studies published from 1990-2022 in Indigenous adult populations of developed countries using PubMed, EMBASE and Global Health databases, without language restriction. We excluded non-peer-reviewed sources, studies with &lt;10 Indigenous people, or studies not covering a 35-64 year minimum age range. Two reviewers independently screened titles, abstracts, and full texts, and extracted data. We assessed quality using "ideal" criteria for population-based stroke incidence studies, the Newcastle-Ottawa Scale for risk of bias, and CONSIDER criteria for Indigenous research. Results: Among 13,041 publications, 24 studies (19 full text, 5 abstracts) from 7 countries met inclusion criteria. Compared with respective non-Indigenous populations (Fig 1), age-standardised incidence rates were greater in Aboriginal and Torres Strait Islander Australians (ratios ranging from 1.7-3.2), American Indians (1.2), Sámi of Sweden/Norway (1.08-2.14), and Singaporean Malay (1.7-1.9), with higher rate ratios at younger ages. Studies had substantial heterogeneity in design and risk of bias. Few investigators reported Indigenous stakeholder involvement. Conclusions: In countries with a very high HDI, available data suggest marked disparities in stroke incidence in Indigenous populations, although there are gaps in data availability and quality. Indigenous stakeholder involvement in studies is infrequently reported. A greater understanding of stroke incidence in these populations is imperative for informing effective societal responses.

Sleep Health as a Determinant of Disparities in Stroke Risk and Health Outcome.

Sleep is essential to human survival and overall vascular health. Sleep health encompasses the objective and subjective qualities associated with one's daily pattern of sleep and wakefulness and has become a growing clinical and public health concern. Impaired sleep duration and quality can increase stroke risk and mediate the relationship between the physical aspects of an individual's environment and disparities in stroke incidence. Here, we review observational studies evaluating the association between sleep health and cerebrovascular disease. We assess the influence on sleep of the physical environment, including the ambient environment with noise levels and the built environment. We also describe the influences on sleep health and stroke risk of social determinants of health, including the chronic stressor of racial discrimination. Finally, we discuss how changes in historical neighborhood characteristics or societal policies can influence the social factors affecting sleep health and stroke risk among socioeconomically disadvantaged groups or ethnic and racial minorities. Given the regional and racial or ethnic differences in stroke risk across the United States, an understanding of novel vascular risk factors, such as the multifaceted role of sleep health, will be critical to develop effective public policies to improve population health.

Racial and ethnic differences in sleep-disordered breathing and sleep duration among stroke patients

ObjectiveWe sought to characterize racial and ethnic differences in pre- and post-stroke sleep-disordered breathing (SDB) and pre-stroke sleep duration. MethodsWithin the Brain Attack Surveillance in Corpus Christi cohort of patients with ischemic stroke (8/26/2010-1/31/2020), pre-stroke SDB risk was assessed retrospectively using the Berlin Questionnaire. Post-stroke SDB was defined by prospective collection of the respiratory event index (REI) using the ApneaLink Plus performed shortly after stroke. Pre-stroke sleep duration was self-reported. We used separate regression models to evaluate the association between race/ethnicity and each outcome (pre-stroke SDB, post-stroke SDB, and pre-stroke sleep duration), without and with adjustment for potential confounders. ResultsThere was no difference in pre-stroke risk of SDB between Black and non-Hispanic white (NHW) participants (odds ratio (OR) 1.07, 95% CI 0.77-1.49), whereas MA (Mexican American), compared to NHW, participants had a higher risk of SDB before adjusting for demographic and clinical variables (OR 1.26, 95% CI 1.08-1.47). Post-stroke SDB risk was higher in MA (estimate 1.16, 95% CI 1.06-1.28) but lower in Black (estimate 0.79, 95% CI 0.65-0.96) compared to NHW participants; although, only the ethnic difference remained after adjustment. MA and Black participants had shorter sleep duration than NHW participants (OR 0.83, 95% CI 0.72-0.96 for MA; OR 0.67, 95% CI 0.49-0.91 for Black participants) before but not after adjustment. ConclusionsRacial/ethnic differences appear likely to exist in pre- and post-stroke SDB and pre-stroke sleep duration. Such differences might contribute to racial/ethnic disparities in stroke incidence and outcomes.

The 2021 William Feinberg Award Lecture Seeking Glocal Solutions to Cerebrovascular Health Inequities.

Global and local ("glocal") disparities in stroke incidence, prevalence, care, and mortality are persistent, pervasive, and progressive. In particular, the disproportionate burden of stroke in people of African ancestry compared to most other racial/ethnic groups around the world has been long standing, is expected to worsen, and so far, has defied solution, largely because conventional risk factors likely account for less than half of the Black versus White disparity in stroke outcomes. While hypotheses such as a differential impact or inadequate evaluation of traditional risk factors by race have been suggested as potentially key factors contributing to lingering racial/ethnic stroke disparities, relatively understudied novel risk factors such as psychosocial stress, environmental pollution, and inflammation; and influences of the social determinants of health are gaining the most attention (and momentum). Moreover, it is increasingly recognized that while there is a lot still to understand, there needs to be a major shift from incessantly studying the problem, to developing interventions to resolve it. Resolution will likely require targeting multilevel factors, considering contemporaneous cross-national and cross-continental data collection, creating scalable care delivery models, jointly addressing care quality and community drivers of stroke occurrence, incorporating policy makers in planning/dissemination of successful interventions, and investing in robust transdisciplinary research training programs that address the interrelated issues of health equity and workforce diversity, and regional capacity building. To this end, our international multidisciplinary team has been involved in conducting several epidemiological studies and clinical trials in the area of stroke disparities, as well as executing career enhancing research training programs in the United States and Africa. This award lecture paper shares some of the lessons we have learnt from previous studies, presents objectives/design of ongoing initiatives, and discusses plans for the future.

Self-Reported Race as a Social Determinant of Stroke Risk in Observational Versus Clinical Trial Datasets

ObjectivesSelf-reported Black (SRB) Americans are approximately twice as likely to have a stroke as self-reported White (SRW) Americans. While social determinants of health and vascular risk factors account for some of the disparity, half the increased risk remains unexplained and may be related to unmeasured real-world factors of the racialized experience. Materialsand Methods In this cohort study, we compared SRB and SRW participants in the Systolic Blood Pressure Intervention Trial (SPRINT) to the same groups in the observational Atherosclerosis Risk in Communities (ARIC) study to evaluate if clinical trial participation mitigates disparities in stroke risk. We set the ARIC baseline at visit 4 and excluded participants with prior stroke to create an ARIC cohort similar in age to SPRINT participants. The study outcome was incident primary stroke. We report hazard ratios from Cox models and inverse-probability weighted Cox models with propensity score matching on participant age, sex, diabetes, atrial fibrillation, and smoking. ResultsWe included 10,094 patients from ARIC and 8,869 from SPRINT, of which 26.1% were SRB. The risk of stroke between SRW participants in SPRINT versus ARIC was not significantly different (IPW-Weighted HR 0.78 [0.52–1.19]). SRB ARIC participants were twice as likely to have a stroke as SRW ARIC participants (IPW-Weighted HR = 1.96 [1.41–2.71]). However, SRB SPRINT participants did not have higher stroke risk compared to SRW SPRINT or ARIC participants (IPW-Weighted HR 0.99 [0.68–-1.77] and 0.95 [.57–1.59], respectively). SRB SPRINT participants in the intensive BP control group had a lower risk of stroke compared to SRB ARIC participants (IPW-Weighted HR = 0.39 [0.20–0.75]). ConclusionsSRB race, compared to SRW race, is associated with an increase in primary stroke risk in the ARIC study but not in the SPRINT trial. The absence of the racial disparity in stroke incidence in SPRINT indicates that aspects of the disparity are modifiable. Population-based interventions that test this hypothesis deserve further attention.

The Incidence of Stroke in Indigenous Populations of Countries With a Very High Human Development Index: A Systematic Review Protocol.

Background and Aims: Despite known Indigenous health and socioeconomic disadvantage in countries with a Very High Human Development Index, data on the incidence of stroke in these populations are sparse. With oversight from an Indigenous Advisory Board, we will undertake a systematic review of the incidence of stroke in Indigenous populations of developed countries or regions, with comparisons between Indigenous and non-Indigenous populations of the same region, though not between different Indigenous populations.Methods: Using PubMed, OVID-EMBASE, and Global Health databases, we will examine population-based incidence studies of stroke in Indigenous adult populations of developed countries published 1990-current, without language restriction. Non-peer-reviewed sources, studies including <10 Indigenous People, or with insufficient data to determine incidence, will be excluded. Two reviewers will independently validate the search strategies, screen titles and abstracts, and record reasons for rejection. Relevant articles will undergo full-text screening, with standard data extracted for all studies included. Quality assessment will include Sudlow and Warlow's criteria for population-based stroke incidence studies, the Newcastle-Ottawa Scale for risk of bias, and the CONSIDER checklist for Indigenous research.Results: Primary outcomes include crude, age-specific and/or age-standardized incidence of stroke. Secondary outcomes include overall stroke rates, incidence rate ratio and case-fatality. Results will be synthesized in figures and tables, describing data sources, populations, methodology, and findings. Within-population meta-analysis will be performed if, and where, methodologically sound and comparable studies allow this.Conclusion: We will undertake the first systematic review assessing disparities in stroke incidence in Indigenous populations of developed countries. Data outputs will be disseminated to relevant Indigenous stakeholders to inform public health and policy research.

Abstract PO-171: Unique stroke disparity and cancer risk in Asian Americans

Abstract Background: Stroke is the fifth-leading cause of death in the US. Previous studies have found that the prevalence of precancerous lesions in patients with ischemic stroke is higher than that in the general population. Studies show that Asian-Americans are more likely to experience a severe ischemic stroke in comparison with other racial groups. Although predisposing risk factors for stroke and stroke epidemiology have been studied extensively, racial-ethnic disparities in stroke incidence and prevalence are well documented but less understood. Methods: This study uses a sample of 18889 adults who self-reported suffering stroke in the Behavioral Risk Factor Surveillance System (BRFSS-2018), which includes five racial and ethnic groups (White, Black, American Indian, Hispanic, and Asian American populations). Factors associated with stroke are used in data analysis. Results: Compared with other racial groups (White/Black/American Indian/Hispanic) in the United States, Asians are at an elevated risk of suffering a stroke. Asians reported a significantly higher rate of stroke in younger age group: in groups aged 18-34, Asians reported the highest rate of having stroke (15.4% vs. White, 1.9%; Black, 2.7%; American Indian, 4.7%; and Hispanic, 10.5%; p&amp;lt;0.001). In addition, among respondents with normal/under-weight, doing exercise, and no smoking, Asians also reported significant higher stroke rates. Specifically, among people being normal- or under-weight; 50.2% of Asians reported having stroke in comparing with White, 29.7%; American Indian, 29.5%; Hispanic, 26.3% and Black, 25.4% (p&amp;lt;0.001). Among people reported doing exercise, Asians (67.0%) reported the highest rate of stroke followed by Hispanic (59.5%), White (58.6%), Black (55.2%) and American Indian (53.3%) (p&amp;lt;0.001). Similarly, among people reported no smoking, Asians (75.6%) also reported a significant higher rate of stroke in comparing with White (66.6%), Hispanic (60.5%), Black (55.7%), and American Indian (44.8%) (p&amp;lt;0.001). More logistic regression results will be reported at presentation. Conclusion: Stroke incidence and prevalence are not uniform. Asian-Americans face unique disparities compared to their racial counterparts’ risk factors for stroke. Elucidating these underlying risk factors and identifying intervention strategies to address the stroke disparities experienced by Asian-Americans will improve both stroke and cancer prevention. Citation Format: Helen Y. Xia, Wenyue Lu. Unique stroke disparity and cancer risk in Asian Americans [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-171.

Identifying Genetic and Biological Determinants of Race-Ethnic Disparities in Stroke in the United States.

In the United States, causes of racial differences in stroke and its risk factors remain only partly understood, and there is a long-standing disparity in stroke incidence and mortality impacting Black Americans. Only half of the excess risk of stroke in the United States Black population is explained by traditional risk factors, suggesting potential effects of other factors including genetic and biological characteristics. Here, we nonsystematically reviewed candidate laboratory biomarkers for stroke and their relationships to racial disparities in stroke. Current evidence indicates that IL-6 (interleukin-6), a proinflammatory cytokine, mediates racial disparities in stroke through its association with traditional risk factors. Only one reviewed biomarker, Lp(a) (lipoprotein[a]), is a race-specific risk factor for stroke. Lp(a) is highly genetically determined and levels are substantially higher in Black than White people; clinical and pharmaceutical ramifications for stroke prevention remain uncertain. Other studied stroke risk biomarkers did not explain racial differences in stroke. More research on Lp(a) and other biological and genetic risk factors is needed to understand and mitigate racial disparities in stroke.

Race and Ethnic Disparities in Stroke Incidence in the Northern Manhattan Study

Background and Purpose- An excess incidence of strokes among blacks versus whites has been shown, but data on disparities related to Hispanic ethnicity remain limited. This study examines race/ethnic differences in stroke incidence in the multiethnic, largely Caribbean Hispanic, NOMAS (Northern Manhattan Study), and whether disparities vary by age. Methods- The study population included participants in the prospective population-based NOMAS, followed for a mean of 14±7 years. Multivariable-adjusted Cox proportional hazards models were constructed to estimate the association between race/ethnicity and incident stroke of any subtype and ischemic stroke, stratified by age. Results- Among 3298 participants (mean baseline age 69±10 years, 37% men, 24% black, 21% white, 52% Hispanic), 460 incident strokes accrued (400 ischemic, 43 intracerebral hemorrhage, 9 subarachnoid hemorrhage). The most common ischemic subtype was cardioembolic, followed by lacunar infarcts, then cryptogenic. The greatest incidence rate was observed in blacks (13/1000 person-years), followed by Hispanics (10/1000 person-years), and lowest in whites (9/1000 person-years), and this order was observed for crude incidence rates until age 75. By age 85, the greatest incidence rate was in Hispanics. Blacks had an increased risk of stroke versus whites overall in multivariable models that included sociodemographics (hazard ratio, 1.51 [95% CI, 1.13-2.02]), and stratified analyses showed that this disparity was driven by women of age ≥70. The increased rate of stroke among Hispanics (age/sex-adjusted hazard ratio, 1.48 [95% CI, 1.13-1.93]) was largely explained by education and insurance status (a proxy for socieoeconomic status; hazard ratio after further adjusting for these variables, 1.17 [95% CI, 0.85-1.62]) but remained significant for women age ≥70. Conclusions- This study provides novel data regarding the increased stroke risk among Caribbean Hispanics in this elderly population. Results highlight the need to create culturally tailored campaigns to reach black and Hispanic populations to reduce race/ethnic stroke disparities and support the important role of low socioeconomic status in driving an elevated risk among Caribbean Hispanics.

Abstract 90: Race, Ethnic, and Sex Disparities in Stroke Incidence in the Northern Manhattan Study

Background: An excess incidence of strokes among blacks vs whites has been shown previously, but data on disparities related to Hispanic ethnicity remains limited. This study examines race, ethnic, and sex differences in stroke incidence in the multi-ethnic, yet largely Caribbean Hispanic, Northern Manhattan Study (NOMAS). Methods: The study population included participants in the prospective population-based NOMAS, followed for a mean of 13±7 years. Cox proportional hazards models were constructed to estimate the hazard ratios and 95% confidence intervals (HR, 95%CI) for the association between race/ethnicity and sex with confirmed incident stroke of any subtype and ischemic stroke, stratified by age and adjusting for sociodemographics and vascular risk factors. Results: Among 3,298 participants (mean baseline age 69±10, 37% men, 24% black, 21% white, 52% Hispanic), 477 incident strokes accrued (394 ischemic, 43 ICH, 9 SAH). The most common ischemic subtype was cardioembolic, followed by lacunar infarcts, then cryptogenic. The greatest incidence rate was observed in blacks (13/1000 person-years [PY]), followed by Hispanics (11/1000 PY), and lowest in whites (8/1000 PY), and this order was observed for crude incidence rates until age 75. By age 85 the greatest incidence rate was in Hispanics. Blacks had an increased stroke risk vs whites overall in fully adjusted models (HR=1.37, 95% CI=1.02-1.84), and stratified analyses showed that this disparity was driven by women age ≥70 (HR=1.69, 1.05-2.73). The increased rate of stroke observed for Hispanics (age/sex-adjusted HR=1.50, 1.15-1.94) was largely explained by education and insurance status (a proxy for socieoeconomic status; HR after further adjusting for these variables=1.15, 0.84-1.58), but remained significant for women age ≥70. Men had an increased rate of stroke compared to women (fully adjusted HR=1.48, 1.21-1.81). Conclusions: This study provides novel data regarding the increased stroke risk among Caribbean Hispanics. Results highlight the need to create culturally-tailored campaigns to reach blacks and Hispanic populations to reduce race/ethnic stroke disparities, and support the important role of low socioeconomic status in driving an elevated risk among Caribbean Hispanics.

Seoulites Social Disparity in Stroke and Types of Health Insurance

이 연구는 의료급여수급권자의 특성에 주목하며 서울시민 뇌졸중 발생에서 의료보장 유형에 따른 격차를 알아보고자 하였다. 연구 자료는 2016년-2017년 최근 2년간 국민건강보험공단 자료 중 서울시 30세 이상 거주자 1,428,153명을 추출하였다. 분석 대상은 2016년 당시 고혈압, 당뇨, 이상지질혈증 의료이용이 있지만 뇌졸중이나 심장질환 발생이 없는 자로 정의하였다. 2016년에서 2017년 사이 뇌졸중의 발생을 종속변수로, 뇌졸중 발생에서 의료보장 유형별 사회적 격차를 측정하고자 하였다. 의료보장 유형은 직장보험료에 따라 3그룹, 지역보험료에 따라 3그룹, 의료급여 수급권자 1그룹 등 총 7개로 구분하였다. 다변량 분석에서 연령, 성별, 장애와 질환 중증도, 2016년과 2017년 각각 해당 만성질환 복약순응도를 통제하였다. 뇌졸중 합병증 발생의 상대불평등 비교를 위해 오즈비와 95% 신뢰구간을 사용하였다. 연구기간 대상자 중 1.4%는 3가지 만성질환이 있고 뇌졸중 발생이 있었다. 직장 최상 보험료 그룹을 기준으로 의료급여 수급권자는 연령과 성별을 보정하고 1.92배 높은 뇌졸중 발생 위험이 있었다. 수급권자의 뇌졸중 발생 상대적 위험은 만성질환의 중증도와 복약 순응도를 보정한 후에도 유의하게 남아있었다. 의료급여 수급권자의 높은 뇌졸중 발생과 관련 만성질환 합병증 관리를 위한 보다 세심한 주의가 필요하다.This study examines the social inequality associated with medical insurance in the incidence of stroke among Seoul residents. Data were derived from ‘2016-2017 national health insurance claims data of 1,428,153 subjects aged 30 and older. Inclusion criteria for samples were defined as 1) having any of three chronic diseases among hypertension, diabetes and dyslipidemia”, but 2) who had not had any stroke or cardiac incidents. The incidence of stroke was the dependent variable. This study sought to examine the social disparity by types of health insurance. The types were divided into 7 groups; 1 group of medical aid, 3 groups of employee insured, and 3 groups of self-employee insured by premiums. Covariates included age, gender, severity (disability or being hospitalized) and medication compliance. Odds ratios (95% CI) were used for the social disparity in stroke incidence. A total of 1.4% of the sample experienced a stroke during the study period. Compared with the highest tertile employee (reference), the medial aid group showed a 1.92 times higher likelihood of having a stroke, adjusting for age and gender. Their higher odds of having a stroke remained statistically significant after further adjustment for severity and medication compliance. Higher stroke incidences of medical aid beneficiaries and related chronic diseases management call for further attention.

Inflammatory cytokines and ischemic stroke risk: The REGARDS cohort.

We studied circulating interleukin (IL)-6, IL-8, and IL-10 concentrations and incident ischemic stroke risk in a biracial cohort, and determined if these cytokines mediated the racial disparity in stroke incidence affecting the black population. The Reasons for Geographic and Racial Differences in Stroke study enrolled 30,237 black and white men and women age ≥45 in 2003-2007. We measured baseline IL-6, IL-8, and IL-10 in a case-cohort study of 557 participants with incident stroke over 5.4 years and 951 participants in a cohort sample. IL-6, but not IL-8 or IL-10, was higher in cases compared to the cohort sample (mean 4.5 vs 3.7 ng/mL; p < 0.001). Only IL-6 was associated with stroke risk factors. Adjusting for age, sex, and race, the hazard ratio (HR; 95% confidence interval) for incident stroke for the highest vs lowest quartile of IL-6 was 2.4 (1.6-3.4). HRs for the highest vs lowest quartiles of IL-8 and IL-10 were 1.5 (1.0-2.1) and 1.4 (1.0-1.9), respectively. After additional adjustment for stroke risk factors, only higher IL-6 remained associated with stroke risk (HR 2.0; 1.2-3.1). Associations did not differ by race. Mediation analyses showed that IL-6 mediated the black-white disparity in stroke risk, but mediation was via IL-6 associations with stroke risk factors. In this biracial population-based sample, IL-6 was strongly associated with risk of incident stroke and mediated the racial disparity in stroke via inflammatory effects of risk factors. Further study on the clinical utility of IL-6 measurement in stroke risk assessment would be helpful.

Abstract TMP58: Preliminary Population-Based Temporal Trends in Stroke Incidence: Racial Disparity and Stroke Incidence From 1993-2015

Introduction: We previously reported that the incidence of stroke was decreasing for whites but stable for blacks from 1993/94 to 2005. We sought to describe recent temporal trends and racial disparities in stroke incidence within our large, bi-racial population, by including 2010 and preliminary data from 2015. Methods: The Greater Cincinnati/Northern Kentucky region includes two southern Ohio and three Northern Kentucky counties on the Ohio River, a population of 1.3 million representative of the US population in terms of sociodemographics and percent black race. Our study ascertained all hospitalized strokes that occurred in the population between 7/1/93 and 6/30/94 and in calendar years 1999, 2005, 2010 and 2015. For 2015, nursing review of medical records is complete but physician review is not; thus 2015 rates are preliminary. The denominator for the calculation of incidence rates (in those aged ≥20 years) was estimated from the U.S. Census Bureau website (www.census.gov). The 95% confidence intervals (CI) for the incidence rates were calculated assuming a Poisson distribution. Rates are age, sex, and race adjusted, as appropriate, and standardized to the 2010 U.S. population. Results: First-ever stroke incidence rates stratified by subtype, race, and study period are presented in the Table. We project that stroke incidence did not significantly change in 2015 vs. 2010 for either blacks or whites, regardless of stroke subtype. Blacks have a substantially higher incidence of stroke compared with whites in all study periods, without significant change in disparity over time. Discussion: In contrast to the significant decline in stroke incidence among whites from 1993-94 to 2005, we did not observe a statistically significant decrease in 2010 and 2015. This may be due to true stabilization of rates over time, or less statistical power to detect smaller declines. The substantial black/white racial disparity in stroke incidence has not changed over time.

Abstract WP235: Hepatocyte Growth Factor and Risk of Stroke in the Reasons for Geographic and Racial Differences in Stroke Study

Introduction: Hepatocyte growth factor (HGF) is a cytokine produced in response to tissue injury and endothelial dysfunction and is correlated with cardiovascular risk factors including hypertension and diabetes. Hypothesis: HGF is associated with risk of stroke, and racial disparities in stroke may be explained by differences in HGF level. Methods: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study enrolled 30,239 black (42%) and white (58%) Americans age 45 and older from 2003-2007. In participants free of baseline stroke, HGF level was measured in a case-cohort study of 534 participants who developed ischemic stroke over 5.4 years and a cohort random sample of 1017 participants. Multivariable linear regression was used to determine correlates of HGF in the cohort random sample. Hazard ratios of stroke by HGF quintile were calculated using Cox proportional hazards models adjusting for stroke risk factors and correlates of HGF. Results: HGF was higher with older age, male sex, cardiovascular disease, smoking, warfarin use and higher CRP, but did not differ by race. Main results are in the figure. Those with HGF in the highest vs. lowest quintile had an HR of incident stroke of 2.12 (CI 1.31-3.41) in the model adjusted for Framingham stroke risk factors. There was no difference in the association by sex or race ( p- interaction &gt; 0.2). As HGF did not differ by race it did not mediate the black-white disparity in stroke incidence. Conclusion: In REGARDS, HGF in the top quintile was associated with a doubling of incident ischemic stroke risk after adjusting for other stroke risk factors. HGF did not mediate the black-white disparity in stroke risk.