Racial Differences in Stroke Incidence Partially Explained

OBJECTIVES: To identify the blood pressure (BP) level associated with the lowest stroke incidence in elderly persons taking antihypertensive medication in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. METHODS: We categorized 13,948 REGARDS participants with hypertension into 3 age groups: 55-64, 65-74 and ≥75 years old and 5 levels of treated systolic BP (SBP): <120 (reference group), 120-129, 130-139, 140-149, and ≥150 mmHg, and 4 levels of diastolic BP (DBP) levels: <70 (reference group), 70-79, 80-89, and ≥90 mmHg. Participants without a history of stroke were followed for a median of 5.7 years (maximum 8.5 years) for incident stroke (n=425). RESULTS: For participants at age 55-64 SBP level <120 mmHg and DBP <70 mmHg were associated with the lowest risk of stroke (incidence per 1,000 person-years: 2.4, 95%Cl: 1.4-4.0 and 2.5, 95%Cl: 1.3-4.7, respectively). Higher stroke risk was observed at SBP ≥140 mmHg. For those aged 65-74, stroke incidence was increased at SBP ≥130 mmHg and at lower DBP levels (with the lowest stroke risk for DBP ≥90 mmHg). For participants ≥75 years SBP ≥150 mmHg was associated with the highest risk of stroke (incidence rate: 15.0, 95%Cl: 10.5-21.3) but no increased risk was observed for SBP between 120-149 mmHg. For DBP, stroke incidence was highest for DBP <70 mmHg (adjusted incidence rate: 9.8; 95%Cl: 6.8-14.1), and lowest for DBP ≥90 mmHg (adjusted incidence rate: 6.5; 95%Cl: 2.9-14.5) (see table). CONCLUSIONS: These results suggest that the lowest risk for stroke for the participants between 55-64 years old are at BP levels <140/70 mmHg, for persons 65-74 we should aim at SBP levels <130 mmHg, and for the oldest patients at SBP <150 with DBP ≥90 mmHg for both groups. For participants aged ≥65 a caution should be kept with the reduction of DBP <90 mmHg, what requires further investigations. Key words: blood pressure, elderly, hypertension, treatment, mortality, stroke.

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Abstract 183: Depressive Symptoms and Incident Stroke in Black and White Participants in the REGARDS Study

Stroke ◽

10.1161/str.43.suppl_1.a183 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

Audrey L Austin ◽

Michael G Crowe ◽

Martha R Crowther ◽

Virginia J Howard ◽

Abraham J Letter ◽

...

Keyword(s):

Risk Factors ◽

Risk Factor ◽

Depressive Symptoms ◽

Racial Differences ◽

Stroke Risk ◽

Depression Scale ◽

Stroke Incidence ◽

Blacks And Whites ◽

The Impact

Background and Purpose: Research suggests that depression may contribute to stroke risk independent of other known risk factors. Most studies examining the impact of depression on stroke have been conducted with predominantly white cohorts, though blacks are known to have higher stroke incidence than whites. The purpose of this study was to examine depressive symptoms as a risk factor for incident stroke in blacks and whites, and determine whether depressive symptomatology was differentially predictive of stroke among blacks and whites. Methods: The REasons for Geographic and Racial Differences in Stroke (REGARDS), is a national, population-based longitudinal study designed to examine risk factors associated with black-white and regional disparities in stroke incidence. Among 30,239 participants (42% black) accrued from 2003-2007, excluding those lacking follow-up or data on depressive symptoms, 27,557 were stroke-free at baseline. As of the January 2011 data closure, over an average follow-up of 4.6 years, 548 incident stroke cases were verified by study physicians based on medical records review. The association between baseline depressive symptoms (assessed via the Center for Epidemiological Studies Depression scale, 4-item version) and incident stroke was analyzed with Cox proportional hazards models adjusted for demographic factors (age, race, and sex), stroke risk factors (hypertension, diabetes, smoking, atrial fibrillation, and history of heart disease), and social factors (education, income, and social network). Results: For the total sample, depressive symptoms were predictive of incident stroke. The association between depressive symptoms and stroke did not differ significantly based on race (Wald X 2 = 2.38, p = .1229). However, race-stratified analyses indicated that the association between depressive symptoms and stroke was stronger among whites and non-significant among blacks. Conclusions: Depressive symptoms were an independent risk factor for incident stroke among a national sample of blacks and whites. These findings suggest that assessment of depressive symptoms may warrant inclusion in stroke risk scales. The potential for a stronger association in whites than blacks requires further study.

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Abstract P555: Plasma Lipids And The Risk For Stroke In The Reasons For Geographic And Racial Differences In Stroke Study (regards).

Circulation ◽

10.1161/circ.141.suppl_1.p555 ◽

2020 ◽

Vol 141 (Suppl_1) ◽

Author(s):

Neil Zakai ◽

Jessica Minnier ◽

Monika M Safford ◽

Lisandro Colantonio ◽

Marguerite M Irvin ◽

...

Keyword(s):

Risk Factors ◽

Racial Differences ◽

Stroke Risk ◽

Plasma Lipids ◽

Cox Regression ◽

Strong Association ◽

Plasma Lipid ◽

Lipid Levels ◽

Cvd Risk ◽

Stroke Incidence

Introduction: Whether plasma lipid levels are associated with stroke risk remains controversial, with even less data for American blacks versus whites. Hypothesis: We hypothesized that abnormal lipid levels are not associated with stroke incidence in either blacks or whites. Methods: The REasons for Geographic And Racial Differences in Stroke (REGARDS) study recruited 30,283 black and white individuals aged 45+ from the contiguous U.S. between 2003 to 2007, participants with a history of stroke at baseline were excluded. Participants were followed until 2018 for stroke events following the WHO definition and confirmed by review of medical records. The association of lipid measures with stroke were assessed using Cox regression models adjusted for traditional CVD risk factors and an age-x-race interaction term. Results: With 27,714 participants (mean age 64.85± 9.43, 59.5% white and 55.4% female), over a median of 11 years of follow up, 1,415 stroke events occurred, of which 599 among blacks. After adjusting for traditional stroke risk factors, there were modest associations between higher total cholesterol and higher LDL, but not higher triglycerides, with stroke risk. There was no evidence of a race interaction. Overall, HDL levels were not associated with stroke risk. However, when stratified by race, whites had a reduced risk of stroke with higher HDL-C, whereas no association was seen among blacks (p-interaction 0.09). Conclusion: In REGARDs, there was a modest association of cholesterol measures with stroke risk. The association for HDL with stroke may be influenced by race, with a less strong association among blacks than among whites.

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Reasons Underlying Racial Differences in Stroke Incidence and Mortality

Stroke ◽

10.1161/strokeaha.111.000691 ◽

2013 ◽

Vol 44 (6, Supplement 1) ◽

pp. S126-S128 ◽

Cited By ~ 42

Author(s):

V. J. Howard

Keyword(s):

Racial Differences ◽

Stroke Incidence ◽

Incidence And Mortality

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Abstract 2535: Urban Versus Rural Differences In Stroke Risk: The CDC Wonder Estimates Of Mortality, And REasons For Geographic And Racial Differences In Stroke (REGARDS) Estimates Of Incidence And Survival After Stroke

Stroke ◽

10.1161/str.43.suppl_1.a2535 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

George Howard ◽

Michael Mullen ◽

John Higginbotham ◽

Dawn O Kleindorfer ◽

Leslie A McClure ◽

...

Keyword(s):

Racial Differences ◽

Stroke Risk ◽

Classification Scheme ◽

Statistical Significance ◽

Stroke Mortality ◽

Stroke Incidence ◽

Risk Of Death ◽

Urban Rural ◽

Regards Study

Introduction: Rural-urban disparities in stroke are poorly understood and incompletely characterized. US stroke incidence, mortality, and survival after stroke have not, to our knowledge, been previously reported by urban-rural status. Methods: Data for US residents over age 45 from the CDC WONDER system were used to describe the age-adjusted stroke mortality rates between 1999 and 2007 for each county in the US, stratified by rurality. Stroke was defined by ICD-10 codes 60-69. Rurality was defined at the county level using the National Center for Health Statistics 6-level classification scheme. Data from the REGARDS Study, a longitudinal cohort study of 30,239 black and white participants aged 45+ from 48 states, were used to estimate the age and sex adjusted hazard ratio for incident stroke, and to assess survival after stroke, using the same urban/rural classification scheme. Results: Between 1999 and 2007, stroke mortality (per 100,000) for those aged 45+ was higher in rural counties for both whites and blacks, with a 20% difference in whites (156.6 for rural versus 131.0 for central metropolitan) and a 32% difference in blacks (237.4 versus 179.6). Among 27,740 REGARDS participants who were stroke-free at baseline with follow-up data, 614 adjudicated stroke events occurred over a mean 4.9 years of follow-up. For whites, incident stroke risk did not change with higher urbanization (HR reported in table ). There was a consistently lower risk of incident stroke with higher urbanization for blacks although this difference did not reach statistical significance (see table ). Follow-up was available on 609 of the stroke events. Risk of death after stroke appeared consistently (although generally non-significantly) lower with greater urbanization (see table ) for both blacks and whites. Discussion: Greater urbanization appears to be associated with lower stroke mortality for both whites and blacks, although differences may be larger for blacks. This difference in mortality may be due to both decreased incidence and survival following stroke for blacks; however, higher mortality for rural whites appears to be only due to decreased survival. Reasons for differences in incidence and survival following stroke may be related to control of vascular risk factors and access to care although further study is required.

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Incidence and Case Fatality at the County Level as Contributors to Geographic Disparities in Stroke Mortality

Neuroepidemiology ◽

10.1159/000449102 ◽

2016 ◽

Vol 47 (2) ◽

pp. 96-102 ◽

Cited By ~ 10

Author(s):

Darwin R. Labarthe ◽

George Howard ◽

Monika M. Safford ◽

Virginia J. Howard ◽

Suzanne E. Judd ◽

...

Keyword(s):

Racial Differences ◽

Stroke Prevention ◽

Case Fatality ◽

Stroke Care ◽

The United States ◽

Hazard Ratio ◽

Mortality Data ◽

Stroke Mortality ◽

Stroke Incidence ◽

Stroke Case

Background: Is the high stroke mortality in the Southeastern parts of the United States driven by differences in stroke incidence or case-fatality? This question remains unanswered. Differences in incidence would underscore the need for stroke prevention, while differences in case fatality would call for improved stroke care. Methods: Quartiles of US counties were defined by stroke mortality, and this gradient was related with stroke incidence and stroke case fatality in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study, where 1,317 incident stroke events (of which 242 were fatal) occurred among 29,650 participants. Results: There was a significant (p = 0.0025) gradient of fatal stroke events in REGARDS (quartile 4 vs. quartile 1 (Q4/Q1) hazard ratio 1.95, 95% CI 1.35-2.81), demonstrating the consistency of REGARDS with national mortality data. The gradient for incident stroke (fatal + nonfatal) was also significant (p = 0.0023; Q4/Q1 hazard ratio 1.29, 95% CI 1.10-1.52). The gradient for stroke case-fatality was marginally significant (p = 0.058), though the OR for Q4/Q1 (1.71, 95% CI 1.13-2.25) was large. Conclusions: Both stroke incidence and case-fatality in REGARDS appear to be contributing, underscoring the need for strengthening both stroke prevention and acute stroke care in order to reduce the disparity.

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Abstract TP211: Fine Particulate Matter (PM2.5) and the Risk of Stroke in the REGARDS Cohort

Stroke ◽

10.1161/str.44.suppl_1.atp211 ◽

2013 ◽

Vol 44 (suppl_1) ◽

Author(s):

Leslie A McClure ◽

Matthew S Loop ◽

William L Crosson ◽

Dawn O Kleindorfer ◽

Brett M Kissela ◽

...

Keyword(s):

Ischemic Stroke ◽

Particulate Matter ◽

Racial Differences ◽

Conditional Logistic Regression ◽

Fine Particulate Matter ◽

Stroke Incidence ◽

Fine Particulate ◽

Increased Risk ◽

Region Of Residence ◽

The Impact

Introduction: Recent work has suggested that there is some association between acute exposures to fine particulate matter with aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) and ischemic stroke; however, the evidence is conflicting. Thus, we assessed whether PM2.5 was associated with ischemic stroke in participants in the Reasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Methods: We used a time-stratified case-crossover design to determine if exposure to PM2.5 was associated with an increased risk of ischemic stroke. We fit conditional logistic regression models to determine the odds ratio of ischemic stroke for those exposed to moderate (PM2.5 15-40 μg/m3) relative to good (PM2.5 ≤ 15 μg/m3) levels of PM2.5. We adjusted for temperature at the time of exposure, and assessed whether the association differed by region of residence (stroke belt vs. non-belt regions). Results: Among 442 participants who experienced an incident ischemic stroke in REGARDS, we found that there was no association with PM2.5 exposure (OR: 0.89, 95% CI: 0.69-1.15), and that there was no impact of region of residence on these results (p for interaction=0.14). Conclusions: We did not confirm earlier research indicating that there is an acute association between PM2.5 and ischemic stroke. More research is needed to understand these conflicting results, and to assess the impact of longer term exposures of PM2.5 on stroke incidence.

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Abstract 52: Contributors to the Rural Excess in Stroke Mortality: The REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

Stroke ◽

10.1161/str.48.suppl_1.52 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

George Howard ◽

Dawn O Kleindorfer ◽

D. L Long ◽

Mary Cushman ◽

Virginia J Howard ◽

...

Keyword(s):

Risk Factors ◽

Risk Factor ◽

Racial Differences ◽

Proportional Hazards ◽

Case Fatality ◽

Stroke Mortality ◽

Rural Regions ◽

Stroke Incidence ◽

Regards Study ◽

The Impact

Introduction: One NIH goal is to investigate the US nationwide rural-urban health disparities; however, few studies provide data to help understand the 30% higher rural stroke mortality. It is unknown if the higher stroke mortality is attributable to a higher incidence of stroke, or to a higher case fatality, in rural regions. Further, the role of risk factors or SES status in higher incidence or case-fatality is unknown. Methods: REGARDS participants stroke-free at baseline (n = 25,090) were stratified by Rural-Urban Commuting Area strata: urban, large rural city/town, or small rural town or isolated region. Participants were followed for incident stroke, and case fatality was defined as death within 30-days of a stroke. Difference in incident stroke was assessed using proportional hazards analysis, and case-fatality by logistic regression, each considered after adjustment for demographic factors, further adjustment for risk factors, and further adjustment for SES. Results: Over an average follow-up of 8.2 years, 1,060 incident strokes occurred, of which 160 died within 30 days. Risk of incident stroke increased with rurality (p = 0.016), with a hazard 1.21-times (95% CI: 1.00 - 1.46) higher in large rural cities/towns, and 1.24-times (95% CI: 1.00 - 1.54) higher in small rural towns or isolated regions (see table). Adjustment for risk factors and SES attenuated the estimated risk by 50%, and the association became non-significant. There was no evidence of a higher case-fatality from stroke in rural regions (p > 0.46). Discussion: The higher stroke mortality in rural regions appears to be attributable to higher stroke incidence, and not to higher case-fatality. Higher stroke incidence in rural regions is partially attributable to a worse risk factor profile and lower SES. Efforts to reduce rural disparity in stroke mortality should focus on preventive strategies, especially those relevant to risk factor development and control, and/or mitigating the impact of lower SES.

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Abstract W P155: Racial Differences in Ischemic Stroke Subtypes: The Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS)

Stroke ◽

10.1161/str.46.suppl_1.wp155 ◽

2015 ◽

Vol 46 (suppl_1) ◽

Author(s):

Brett Kissela ◽

Jane Khoury ◽

Kathleen Alwell ◽

Charles J Moomaw ◽

Daniel Woo ◽

...

Keyword(s):

Racial Differences ◽

Small Vessel Disease ◽

Population Based ◽

Incidence Rates ◽

Small Vessel ◽

Point Estimate ◽

Stroke Incidence ◽

Statistical Variation ◽

Stroke Study ◽

Using Data

Background: It is well known that blacks have higher stroke incidence rates than whites. It is commonly believed that whites have more cardioembolic (CE) and large vessel (LV) ischemic strokes (IS). However, using data from 1993-94, we showed that blacks have higher rates of every IS subtype. We sought to see if this pattern persisted in 2010 within a large, biracial population of 1.3 million representative of the US. Methods: The GCNKSS is a population-based stroke epidemiology study from five counties in the Greater Cincinnati region. During 2010, we captured all hospitalized strokes by screening ICD-9 codes 430-436. We also captured out-of-hospital strokes by sampling primary care offices and nursing homes. Study nurses abstracted all potential cases. Physicians adjudicated each possible event and then further subtyped IS based on available test results using established methods. Incidence rates per 100,000 and associated 95% confidence intervals (CI) were estimated for each subtype using first-ever IS, with weighting of out-of-hospital event sampling, then age- and sex- adjusted to the 2000 US population. Black/white risk ratios (RR) and 95% CI were also calculated. Results: In 2010 there were 2219 IS in 2116 patients, and 1693 first-ever IS. Of the 1693 incident IS, 944 (57%) were female, 346 (21%) black, with mean age 69 years. There were 285 (18%) small vessel, 465 (27%) CE, 218 (12%) LV, 107 (6%) other identified cause, and 617 (37%) undetermined. The table shows incident IS rates by subtype and the associated RR. For each subtype of IS, blacks had a higher point estimate than whites in 2010. In 2010, the RR CI’s cross 1.0 for CE and LV, thus the RR is not statistically significant. Conclusion: It is not clear if these data represent significant differences for CE and LV subtypes in 2010 or statistical variation between periods. Regardless, stroke prevention efforts for blacks should include strategies relevant to all IS subtypes, and not just those for small vessel disease.

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Abstract W P176: Self-reported Pre-Stroke Physical Activity Levels Influence Functional Ability Following Incident Stroke

Stroke ◽

10.1161/str.46.suppl_1.wp176 ◽

2015 ◽

Vol 46 (suppl_1) ◽

Author(s):

Michelle N McDonnell ◽

Susan L Hillier ◽

David L Roth ◽

Suzanne E Judd ◽

William E Haley ◽

...

Keyword(s):

Physical Activity ◽

Racial Differences ◽

Functional Ability ◽

Length Of Hospital Stay ◽

Stroke Recovery ◽

Activity Levels ◽

Stroke Event ◽

Stroke Incidence ◽

Post Stroke ◽

One Year

Background and Purpose: Emerging evidence suggests that stroke recovery is influenced by pre-stroke physical activity (PA). The purpose of this study was to examine whether prospectively collected pre-stroke PA levels were associated with functioning one year post-stroke in survivors of a first stroke. Methods: PA was assessed during baseline interviews of participants in the REasons for Geographic and Racial Differences in Stroke (REGARDS) observational study. Participants who experienced a first-ever stroke event during follow up were enrolled in an ancillary study. Approximately 12 months following stroke incidence, survivors and their informants were interviewed by telephone, and an in-home assessment of functional ability was conducted (n = 203). The association between pre-stroke PA and post-stroke function was assessed. Results: Participants reported baseline PA as either no vigorous PA (n = 65), or PA once or more per week (n = 138). Individuals who exercised at least once per week had significantly greater function at one year following stroke as assessed with the NIHSS, the Barthel Index and the Stroke Impact Scale physical domain score. In the multivariate model, race, education, sex, age, length of hospital stay and discharge destination were associated with functioning and attenuated this relationship. However, the significant association between pre-stroke PA and the NIHSS remained (p = 0.003). Conclusions: Self-reported PA prior to stroke was associated with significantly lower NIHSS scores one year after stroke. Other physical function measures were attenuated by factors such as female sex and African American race which were strongly related to poorer function.

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