Strokes and African Americans

Strokes and African-Americans

African-Americans are reported to be nearly twice as likely to experience a stroke as their white counterparts however, African-Americans are much less likely to know the risk-factors and symptoms of stroke or to seek early treatment. The purpose of this study is to examine the issue of African-Americans and stroke. The significance of this study is the additional knowledge that will be added to the already existing base of knowledge in this area of study. The methodology employed in this study is of a qualitative and interpretive nature and has been conducted through a review of literature in this area of study.

Strokes and African-Americans

African-Americans are reported to be nearly twice as likely to experience a stroke as their white counterparts however, African-Americans are much less likely to know the risk-factors and symptoms of stroke or to seek early treatment.

Purpose of the Study

The purpose of this study is to examine the issue of African-Americans and stroke.

Significance of the Study

The significance of this study is the additional knowledge that will be added to the already existing base of knowledge in this area of study.

Methodology

The methodology employed in this study is of a qualitative and interpretive nature and has been conducted through a review of literature in this area of study.

Introduction

According to the National Stroke Association (2010) stroke is "…the third leading cause of death in American and the leading cause of disability." In addition, it is reported that 80% of strokes are preventable." (National Stroke Association, 2010) A stroke or 'brain attack' is reported to occur "…when a blood clot blocks an artery (a blood vessel that carries blood from the heart to the body) or a blood vessel (a tube through which the blood moves through the body) breaks, interrupting blood flow to an area of the brain. When either of these things happen, brain cells begin to die and brain damage occurs." (National Stroke Association, 2010)

Brain cells die during the stroke and the individual loses abilities including those such as speech, movement and memory. (National Stroke Association, 2010) Some individuals who experience a stroke only have minor problems resulting from the stroke however, individuals who have larger strokes may experience paralysis on one side and lose their ability to speak. Some individuals recover completely from having had a stroke however, "more than 2/3 of survivors will have some type of disability." (National Stroke Association, 2010)

Literature Review

African-American adults are reported to be 1.7 times more likely to have a stroke than their white adult counterparts according to the Office of Minority Health (2010). Men are stated to be 60% more likely to die from a stroke than are their White adult counterparts." (Office of Minority Health, 2010) A Centers for Disease Control health interview states findings that "African-Americans stroke survivors are more likely to become disabled and have difficulty with activities of daily living than their non-Hispanic white counterparts." (Office of Minority Health, 2010) The following chart lists age-adjusted percentages of stroke among persons 18 years of age and over.

Figure 1

Age-adjusted Percentages of Stroke Among Persons 18 years of age and over (2007)

Age-adjusted percentages of stroke among persons 18 years of age and over, 2007

African-American

White

African-American/

White Ratio

Men and Women

3.7

2.2

1.7

Men

2.8

2.1

1.3

Women

4.2

2.2

1.9

Source: CDC 2009. Summary Health Statistics for U.S. Adults: 2007. Table 2.

http://www.cdc.gov/nchs/data/series/sr_10/sr10_240.pdf[PDF | 8.43MB]

The following chart lists the death rate from strokes in 2006.

Figure 2

Age-Adjusted Stroke Death Rates per 100,000 cases (2006)

Age-Adjusted Stroke Death Rates per 100,000 (2006)

Non-Hispanic Black

Non-Hispanic White

Non-Hispanic Black/Non-

Hispanic White Ratio

Men

68.4

41.7

1.6

Women

58.0

41.5

1.4

Total

62.8

41.9

1.5

Source: CDC, 2009. National Vital Statistic Report. Vol. 57, Num 14 Table 17.

http://www.cdc.gov/nchs/data/nvsr/nvsr57/nvsr57_14.pdf[PDF | 1.7MB]

The following chart contains data from NHIS from 2001-2001 which was analyzed to examine stroke-related disability.

Figure 3

Age-adjusted Percentage of Stroke Survivors, aged 18 years and over who report difficulty in performing activities 2000-2001

Limitation of Activity

African

Americans

Non-Hispanic

White

African

American/Non-

Hispanic White

Ratio

Walk 1/4 of a mile (3 city blocks)

45.1

36.5

1.2

Walk up 10 steps without resting

42.4

28.6

1.5

Stand or be on your feet for 2 hours

50.2

41.1

1.2

Sit for about 2 hours

16.4

10.7

1.5

Stoop, bend or kneel

44.8

37.7

1.2

Reach up over your head

21.6

14.7

1.5

Use your fingers to grasp or handle small objects

18.2

11.1

1.6

Lift or carry something as heavy as 10 pounds (e.g. grocery bag)

40.6

24.6

1.7

Push or pull large objects like a living room chair

45.2

32.5

1.4

Go out to things like shopping, movies, or sporting events

30.1

20.0

1.5

Participate in social activities like visiting friends

23.8

16.2

1.5

Do things to relax at home (reading, watching TV, sewing)

9.6

5.4

1.8

Source: CDC 2005. Differences in Disability Among Black and White Stroke Survivors -- United States, 2000-2001. MMWR 54(1): 3-6.

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5401a2.htm

According to statistics, one-half of all African-American women will die from stroke or heart disease. (National Stroke Association, 2010) African-Americans are reported to be twice as likely to die from strokes as White Americans as the rate of first stroke in African-Americans is reported to be "almost double that of Caucasians, and strokes tend to occur earlier in life for African-Americans than Caucasians." (National Stroke Association, 2010) African-Americans are more affected by stroke than any other racial group in the U.S. population and it is reported that it is not clear why that this is true although there are identified factors that play a primary role including that African-Americans have a higher rate of the following:

(1) High blood pressure which is the number one risk factor for stroke. One of every three African-American suffer from high blood pressure;

(2) Diabetes -- also increases the risk for stroke;

(3) Sickle cell anemia -- the most common genetic disorder among African-Americans. Sickle shaped cells often block a blood vessel to the brain causing stroke;

(4) Smoking -- doubles the risk for stroke; and (5) Obesity. (National Stroke Association, 2010)

For the individual with one of more of these risk factors it becomes "…even more important to learn about stroke symptoms and response and the lifestyle and medical changes that can be made to prevent a stroke." (Office of Minority Health, 2010) Interesting facts stated by the Office of Minority Health include the following facts: (1) African-Americans have twice the mortality from stroke compared with Caucasians; (2) African-Americans have more severe and disabling strokes compared with Caucasians; (3) African-American women have a lower 1-year survival following ischemic stroke (caused by a blood clot) compared with Caucasians; (4) African-Americans have twice the risk of first ever strokes compared with Caucasians; (5) Among those aged 20 to 44 years of age, African-Americans are 2.4 times more likely to have a stroke compared with Caucasians; and (6) African-Americans are significantly less likely to receive tPA, the only FDA-approved treatment for stroke, compared with Caucasians." (Office of Minority Health, 2010) According to Neipris (1998) the following may help the African-American individual avoid the experience of having a stroke:

(1) Have your blood pressure checked as often as your doctor suggests. The most important risk factor for stroke is high blood pressure. It's called the "silent killer" because there are no symptoms. About one in three African-Americans (both men and women) has high blood pressure. If you have high blood pressure, you may need to take medicine to keep your blood pressure under control.

(2) Know your cholesterol numbers. Ask your doctor about a cholesterol blood test. If your cholesterol numbers are borderline or high risk, work with your doctor to lower your risk of heart disease and stroke.

(3) Eat right to reduce stroke risk. Just keep a few points in mind:

(a) Reduce sodium (salt). Avoid canned foods, where sodium content is often high. Avoid lunch meats that are high in sodium. (b)Reduce cholesterol. Go for lean meats, such as chicken and fish. Trim skin and fat from chicken. (c) Reduce your calories. This is important if you are trying to reach a healthy weight. Limit portion sizes. Look at the calorie amounts of foods by reading the label. (d) Increase fiber. Go for high-fiber foods, such as whole-grain breads. Have beans, a great source of lean protein as well as fiber. (e) Have plenty of fruits and vegetables. (f) Don't fry. Instead, prepare foods by baking, broiling and steaming.

4) Quit smoking if you smoke. Smoking not only raises your risk for heart attack and lung cancer. It also doubles your risk for stroke. Get smoking cessation advice from your doctor. Remember, your stroke risk starts to drop the moment you quit.

5) Be active - exercise! Chose an activity you enjoy that keeps up your heart rate, like jogging, cycling or even taking a brisk walk. Regular exercise helps you to reach and maintain a healthy weight. Adults should do moderate to intense exercise for at least 30 minutes on most days of the week. Talk to your doctor before you start to exercise or ramp up your exercise routine.

6) If you drink alcohol, drink only in moderation. Drinking an average of more than one alcohol-containing drink a day (for women) or more than two drinks a day (for men) raises blood pressure, which is a stroke risk. Drinks with alcohol, especially beer, are also a source of empty (non-nutritional) calories, which can lead to overweight/obesity. (Neipris, 1998)

Gorelick (1998) reports that excess mortality is "a pervasive theme in the African-American community. African-Americans are more likely to die of more chronic diseases, occupational injuries, homicides and violent crimes and have more disproportionate infant mortality." The following figure lists the comparative life expectancy in the United States of White women and men and Black women and men.

Figure 5

White women

79.6 y

Black women

73.8 y

White men

72.9 y

Black men

64.6 y

Comparative Life Expectancy in the United States

(Gorelick, 1998)

Gorelick (1998) reports that in the U.S. "…excess stroke mortality has been substantial for both African-Americans and whites in the southeastern portion of the country, an area known as the Stroke Belt. Stroke mortality is not uniform in this region. The highest rates appear along the coastal plain of Georgia and the Carolinas in an area dubbed the stroke "buckle." Recent study suggests a shift of the Stroke Belt to the lower Mississippi River Valley." Stroke mortality rates are reported to have recently fallen in this region however it is stated that there "…still remains substantial excess stroke mortality. The reason for this geographically-based excess remains uncertain. (Gorelick, 1998) It has been suggested, according to Gorelick that "…death certificate coding practices, the proportion of African-Americans in the region, regional case fatality, and socioeconomic factors are variables that are unlikely to explain the excess. Cardiovascular, genetic, or environmental factors may explain the disproportion, at least in part, and should be considered the focus of future study in this region." (1998) The following figure lists the stroke incidence rates cited by Gorelick (1998).

Figure 6

Stroke Incidence Rates

Study

Incidence Rate

South Alabama25

208/100-000 blacks1 109/100-000 whites1

Lehigh Valley26

2.43 black:white standard morbidity ratio 4.50 black:white standard morbidity ratio for age

Northern Manhattan27

567/100-000 black men1 351/100-000 white men1 716/100-000 black women1 326/100-000 white women1

Greater Cincinnati / Northern Kentucky28

288/100-000 African-Americans (first-ever stroke) 2 and 411/100-000 African-Americans (first-ever and recurrent stroke) 2 vs. 179/100-000 whites (first-ever stroke in Rochester, MN) 2

Northern Manhattan29

233/100-000 blacks1 93/100-000 whites1

1 Age-adjusted rates;

2 age- and sex-adjusted rates.

(Source: Gorelick, 1998)

Gorelick writes that there is a "paucity of recent studies of stroke prevalence" and states that African-Americans have a higher incidence of cerebral infarction, subarachnoid hemorrhage, and intracerebral hemorrhage.' (1998) Gorelick notes that these rates "…are generally disproportionately higher for African-Americans at relatively younger ages." (1998) It is reported that Broderick and colleagues "…showed that African-Americans who were up to 75 years had about twice the risk of subarachnoid hemorrhage and 2.3 times the risk of intracerebral hemorrhage when compared with whites. For African-Americans over 75 years of age, however, the odds ratio for intracerebral hemorrhage was only 0.23." (Gorelick, 1998)

It is reported that in the Kaiser Permanente study, "…the risk of hospitalization for subarachnoid hemorrhage was about 2.5 times higher and that of intracerebral hemorrhage 2.3 times higher for African-Americans than whites." (Gorelick, 1998) Gorelick also states that Ischemic stroke subtypes differ by race in that "African-Americans may be at higher risk for lacunar infarction and large-artery intracranial occlusive disease, whereas whites may be more prone to cerebral embolism, transient ischemic attack, and possibly extracranial occlusive disease. Debate has occurred concerning the possible racial propensity for intracranial or extracranial occlusive disease. Data to support the belief that racial differences exist in the anatomic distribution of occlusive cerebral vascular disease originate from a variety of types of studies such as autopsy, angiography, noninvasive blood flow, and clinical trials. Much of this data, however, emanates from referral centers or select populations that may not be representative of the community at large. Thus, it may be premature to conclude that there are clear-cut racial differences in the distribution of occlusive cerebral vascular disease. The weight of the available data suggests that African-Americans are more likely to have symptomatic intracranial occlusive disease, whereas the results are mixed with regard to a racial propensity for symptomatic or asymptomatic extracranial occlusive disease. Several studies suggest that intimal-medial thickness may be greater at some asymptomatic extracranial sites in African-Americans but at other sites in whites." (Gorelick, 1998) Gorelick reports that the exact reason for "…racial differences in the frequency of stroke subtype and the possible differences in the anatomic distribution of occulusive cerebral vascular disease is not known." (1998) However, Gorelick states that the presumption has been made that it is due to "differences in the frequency, severity and control of major cardiovascular risk factors such as hypertension." (1998)

The explanations that have been proposed for the reason that there is excess stroke mortality and risk in African-Americans include those as follows: (1) higher prevalence of cardiovascular risk factors; (2) greater severity of risk factors or greater sensitivity to the risk factors; and (3) lack of access to care. (Gorelick, 1998) As traditional cardiovascular disease risk factors including hypertension and diabetes mellitus do not account for the disproportionate burden of stroke in the African-American population other conventional factors may play a role including socioeconomic status (SES).

Measures that are commonly used include: (1) education; (2) income; (3) occupation; (3) employment status; (4) indexes of social class; (5) measures of living conditions; (6) area-based measures; (7) life-span measures; and (8) measures of income inequality. (Gorelick, 1998) Primary measures of SES are stated to include: (1) education; (2) occupation; and (3) income. (Gorelick, 19989) SES is stated to have been a predictor of "all-cause mortality or coronary disease mortality." (Gorelick, 1998) African-Americans have been historically underrepresented in clinical trials however, the U.S. government is reported to have set mandates in diversity in the conduction of population studies and the National Institute of Health has recruited women and minorities for such studies. The following shows the representation of African-American in stroke trials.

Figure 7

Representation of African-Americans in Stroke Trials

Study

Total Patients, n

% Black

Ticlopidine Aspirin Stroke Study111 (1989)

16

Canadian American Ticlopidine Study112 (1989)

28

North American Symptomatic Carotid Endarterctomy Trial (70 -- 90% stenosis group) 113 (1991)

3

NINDS rt-PA Study114 (1995)

27

Asymptomatic Carotid Atherosclerosis Study115(1995)

2

Clopidogrel vs. Aspirin in Patients at Risk of Ischemic Events (CAPRIE)116 (1996)

6431 (Stroke subgroup)

9

African-American Antiplatelet Stroke Prevention Study (AAASPS)117 (ongoing, as of 10/19/98)

Source: Gorelick (1998)

It was reported in the work entitled "African-American Have Highest Stroke Rate, Southerners More Likely to Die" that African-Americans age 65 and younger "are more than twice as likely to have a stroke compared with Caucasians in any region, and people who have a stroke are more likely to die in the South than elsewhere, according to researcher at the University of Alabama at Birmingham (UAB) School of Public Health." (Science Daily, 2010) The findings are from UAB's 'Reasons for Geographic and Racial Differences in Stroke' (REGARDS) study that included in excess of 30,200 participants in the United States. The report is stated to be "among the first to show major regional and racial disparities in stroke rates." (Science Daily, 2010)

A report published March 1st, 2010 reports that findings of a meeting of the American Stroke Association (ASA) stated the following:

(1) Among people aged 45 to 54, there were 192 strokes per 100,000 African-Americans vs. 74 strokes per 100,000 whites.

(2) Among people aged 55 to 64, there were 387 strokes per 100,000 African-Americans vs. 204 strokes per 100,000 whites.

(3) Among people aged 65 to 74, there were 713 strokes per 100,000 African-Americans vs. 439 strokes per 100,000 whites.

(4) Among people aged 75 to 84, there were 1,095 strokes per 100,000 African-Americans vs. 925 strokes per 100,000 whites. (Laino, 2010)

Laino (2010) additionally reports that African-Americans were found to be "less likely to have regular follow-up exams for management of risk factors."

In a study conducted and reported by Howard, et al. (2006) findings show that "across age and sex strata, the black-to-white stroke mortality ratio was consistently higher for southern states with an average black-to-white stroke mortality ratio that range from 6% to 21% higher among southern states that in nonsouthern states." (Howard, et al., 2006)

The work entitled "Reducing Stroke Risk in African-Americans" reports that African-American children who have siblings with sickle cell disease (SCD) are more likely to have "abnormal, 'twisted' arteries in the brain, which may lead to an elevated risk of stroke in adulthood." (St. Jude Children's Research Hospital, 2003) It is reported that these arteries are similar to those common viewed in older patients with hypertension however these types of arteries are rarely viewed in children. It is stated that this findings "may help explain why African-American men between 33 and 44 years of age are three to four times more likely to suffer a stroke than American white men of the same age." (St. Jude Children's Research Hospital, 2003)

According to the work of Brenner, et al. (2010) in the work entitled "Awareness, treatment, and control of vascular risk factors among stroke survivors" reported is the assessment of "…the prevalence, treatment, and control of hypertension, diabetes, and dyslipidemia among stroke survivors vs. stroke-free control subjects" in a cross-sectional analysis from the "Reasons for Geographic and Racial Differences in Stroke (REGARDS) study cohort, which includes oversampling from the Stroke Belt and African-Americans." (Brenner, et al., 2010) Interviews with patients were conducted via telephone and home visits were made for taking blood pressure and glucose readings and lipid measurements. The study involved 2930 participants/patients who had reported a stroke or transient ischemic attack (TIA) (stroke survivors) and 24,886 participants who did not report a past stroke or TIA (control subjects). Control measures included the recognition, treatment, and control of hypertension, diabetes, and dyslipidemia" (Brenner, et al., 2010) The study results are specifically as follows:

"Stroke survivors were more likely to have unrecognized hypertension (18.7% v 13.5%, P < .0003), unrecognized stage 2 hypertension (4.4% v 2.2%, P < .0006), and unrecognized diabetes (4.2% v 3.2%, P < .026) versus control subjects. Stroke survivors were more likely to be treated for hypertension (92.4% v 89.0%, P < .0001), diabetes (88.3% v 81.4%, P < .0001), and dyslipidemia (76.3% v 61.9%, P < .0001). However, despite treatment, stroke survivors were more likely to have hypertension (33.3% v 30.4%, P=.0074) and stage 2 hypertension (9.1% v 7.6%, P=.017). Predictors of unrecognized and undertreated risk factors in stroke survivors include increasing body mass index, black race, and lower education." (Brenner, et al., 2010)