Download Cardiovascular Disease in Black Women

Cardiovascular Disease in Black Women

Rozann Hansford, R.N. MPH Candidate

Cardiovascular Heart Disease Cardiovascular disease (CVD) refers to a wide variety of heart and blood vessel disorders including CHD, HTN, stroke, rheumatic heart disease  Coronary Heart Disease (CHD) refers to several disorders that decrease blood supply to the heart muscle 

Pathophysiology of CHD Atherosclerosis is the underlying disease process  Typically begins in childhood  Slowly progressive,thickening of the inner layer of the arteries walls  Incidence increases with age  Not an inevitable consequence of aging 

Pathophysiology of CHD Disease progression starts with fat deposition and advances to fatty streaks with lipid core and calcium deposits  As atherosclerosis progresses, arteries narrow enhancing possibility of endothelial disruption, hemorrhage and occlusive thrombosis (3) 

Pathophysiolgy of CHD Contributing factors include inflammatory, immunologic and hemostatic processes involving multiple systems and cellular types  Persons most likely to suffer a myocardial infarction have 70% occlusion as previously thought 

Biological differences between blacks and whites? 

It is not known whether cellular and molecular mechanisms of atherogenesis differ between races

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Blacks with hypertension respond less to angiotensin converting enzyme (ACE) inhibitors

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Blacks demonstrate greater fibrinolysis when receiving tissue plasmin activator (TPA) for myocardial infarction (4)

Epidemiology of CHD in Black Women (US) Black Americans experience a higher morbidity/mortality compared with other racial/ethnic groups and have the highest age adjusted CHD mortality (1). CVD accounts for 41.6% of deaths in black women  CHD death rates are 67% higher for black women compared to white women 

Epidemiology of CHD in Black Women 

CHD is particularly prevalent in black women younger than 55 years old who have 2.5 times the risk of CHD death compared to white women (6).

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Are black women deriving the same benefit from estrogen as white women?

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Black women have 2 times the rate of angina compared with white women and five times the rate of angina compare to black men.

CHD Risk Factors in Black Women Framingham Heart Study….defined and quantified cardiac risk factors and related finding to cardiovascular outcomes  Enrollment limited almost exclusively to whites  Should this data be generalized to include all racial/ethnic mixes? 

CHD Risk Factors in Black Women

Clinical Trials 

CHS…Cardiovascular Heart Study..enrollment limited to white men and women

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Charleston Heart Study, MRFIT study and Chicago Heart Study… enrollment limited to men

CHD Risk factors in black women Clinical trials 

Atherosclerosis in the Community (ARIC) included large cohort of black women • Four communities in the US, 1987-1997 • Included 14,026 black and white men • Included 10 years follow-up • Hypertension a particularly strong risk factor in black women

CHD Risk Factors in black women 

National Health and Nutrition Evaluation Survey I (NHANES I) • 14,000 black and white persons from 1982-1992 • Elevated systolic blood pressure and smoking in black women predictive of CHD • Excess risk of CHD in black women relates to higher levels of identified risk factors

CHD Risk factors in black women Smoking 

Not specifically studied in black women

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In women, first MI’s occur 19 years earlier if woman smokes

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May be a strong risk factor in black women because of effects of co-morbidity (black women have a high incidence of HTN,diabetes and hypercholesterolemia

CHD Risk factors in black women

Hypertension A major risk factor for the development of CHD and stroke.  Associated with pathologic changes in the arterial walls and endothelium, decreased of small peripheral arteries, increased left ventricular wall thickness and abnormal diastolic function (15). 

CHD risk factors in black women

Hypertension 

Particularly strong risk factor in Black women (ARIC) study • Left ventricular hypertrophy is an independent risk factor for development of CHD

CHD risk factors in black women

Diabetes 

Incidence of CHD is 2 to 4 times higher in persons with Diabetes

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Incidence of type II Diabetes is 9.1% in black women compared with 4.5% in white women

CHD risk factors in black women

Diabetes 

Implicated as a possible etiology of increased CHD incidence in young black women  Animal Studies suggest that hyperglycemia and hyperinsulinemiainsulin may prevent the cardiovascular effects of insulin  Black women have a higher incidence of obesity and diabetes relative to white women,protection from CHD that sex usually provides may not be as strong in black women

CHD risk factors in black women

Syndrome X Syndrome X…cumulative effects of hypertension, glucose intolerance and dyslipidemia  Associated with a higher cardiovascular mortality  Has a synergistic effect on atherogenesis  Seen more often in black women than other racial/ethnic mixes 

CHD risk factors in black women Obesity Approximately 75% of African American women are obese, more than any other racial gender mix  Body Mass Index (BMI), body fat distribution and central obesity are all predictive of CHD risk in women  Major cause is inactivity 

CHD risk factors in black women

Hypercholesterolemia 

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Incidence of elevated cholesterol is 20% in black women..relationship to CHD not studied in black women In black men, relationship of elevated cholesterol to CHD development is confusing, may have implications for black women

CHD risk factors in black women

Hypercholesterolemia 

In whites, higher socioeconomic is associated with higher HDL’s..the reverse is true in black men

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Black men have higher levels of lipoprotein but these levels are less predictive of CHD in black men compared to white men

Socioeconomic factors CHD in black women results from a complex interplay between established risk factors, access to health care, behavioral and coping mechanisms and socioeconomic status  Differences in access to care and economic factors may play an important role 

Socioeconomic factors 

Because black women do not access health care facilities as often as white women, community based interventions at churches, work places and schools may be useful for prevention  Heart, Body and Soul partnership between Clergy and Johns Hopkins University minimizes barriers associated with mistrust of health personal

Research needed!!! Insufficient data available for resolving questions related to racial/gender comparisons  Need to determine if differences, clinical paradoxes and inconsistencies are related to chance findings, artifacts in reporting, environmental differences or biological differences 

Research Needed!!! Data already collected needs to be pooled and examined; a first step would include a national screening policy  Culturally validated data tools needed  Need to study efficacy of prevention strategies 

Conclusions 

Most large scale clinical trials to date have excluded black women. Results have been generalized to include black women and this may be very misleading

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Small studies, incidental findings, responses to some meds and animal research hint at the possibility of biological differences between black women and other racial/ethnic mixes

Conclusions Black women tend to get CHD 10 years earlier than white women. The reasons for this though hypothesized, have not been established.  Hypertension appears to be the single most important risk factor for the development of CHD black women. 

Conclusions 

The excessive incidence of CHD in black women is likely due to a complex relationship between social, behavioral, genetic and economic factors. Teasing out the contributions of these factors so that appropriate public health measures can be implemented is likely to be a very difficult task!

References 

1. Gillum RF. Cardiovascular Disease in the United States: an epidemiologic overview. In: Saunders E, ed. Cardiovascular diseases in blacks. Philadelphia, Pa: FA Davis, 1991:3-16.  2. Gillum RF, The epidemiology of cardiovascular disease in Black Americans. New Eng J Med. 1996;335:1597-1599.  3. Ross R. The pathogenisis of atherosclerosis: a perspective for the 1990’s. Nature. 1993;362:801-809.

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8. Keil J, Sutherland s, Hames C, Lackland D, Gazes P, Knapp R, Troyer HA. Coronary disease mortality and risk factors in black and white men: results from the combined Charleston SC and Evans County Georgia, Heart Studies. Arch Intl Med. 1995;155:15211527.  9. Smith GD, Neaton JD, Wentworth D, Stamler R, Stamler J. Mortality differences between black and white men in the USA: contribution of income and other risk factors among men screened for MRFIT. Lancet. 1998;351:934-939.

• 13. Hansen EF, Andersen LT, Von Eyben FE. Cigarette smoking and age at first acute myocardial infarction and influence of gender and extent of smoking. Am J Cardiol. 1993;17:1439-1442. • 14. Tsang T, Barnes M, Gersh B, Bernard J, Hayes S. Risks of Coronary Heart Disease in Women: Current understanding and Evolving Concepts. Mayo Clinic Proceedings. 2000;75:1289-1303. • 15. Sempos CT, Cleeman JI, Carroll MD. Prevalence of High Blood Pressure among US adults: an update based on guidelines from the second report of the National Cholesterol Education Program Adult Treatment Panel. JAMA. 1993;269:3009-3014.

• 20. Willet WC, Manson JE, Stampfer MJ et al. Weight, weight change, and coronary disease in women:risk within the normal weight range. JAMA. 1995;273:461-465. • 21. Stevenson JC, Cook D, Godsland IF. Influence of age and menopause on serum lipids and lipoproteins in healthy women. Atherosclerosis. 1993;98:83-90. • 22. Freedman DS, Strogatz DS, Eaker E, Joesoef MR, Destefano F. Differences between blackand white men in correlates or high density lipoprotein cholesterol. Am J Epidemiol 1990. 132:656-669.