The Disproportionate Impact of Hypertensive Cardiovascular Disease in African Americans: Getting to the Heart of the Issue

The prevalence of hypertension in African Americans is among the highest in the world. Persons in this group develop hypertension at a younger age than non-African Americans and develop more severe complications, including stroke, cardiovascular disease, and renal failure. The factors that impart this high risk to this population remain poorly understood and, undoubtedly, environmental factors overshadow genetic predisposition. While identifying the pathophysiologic and environmental factors that contribute to ethnic disparity in disease is important, finding a long-term solution is crucial. Steps that can have an important impact on health outcomes of African Americans are presently available. Awareness of ethnicity as a risk factor for hypertension can allow health care providers to identify persons who are likely to benefit most from early, aggressive intervention. Modifiable factors such as smoking, diet, and sedentary lifestyle, as well as undertreatment of hypertension by physicians, can be targeted immediately.     

Blood pressure and mortality risk in older people: comparison between African Americans and whites

OBJECTIVES: To determine the risk from hypertension for all-cause mortality in a racially mixed sample of community-dwelling older adults. DESIGN: Baseline blood pressure was assessed between 1985 and 1986 in a sample of persons 65 years of age and older from five counties of the Piedmont of North Carolina (N = 4,162). All-cause mortality was monitored annually over the subsequent 6 years as part of the Established Populations for Epidemiologic Studies of the Elderly (EPESE) sponsored by the National Institute on Aging. SETTING: Eighteen percent of all respondents in the sample had a systolic blood pressure of > 160 (17% for whites and 18% for African Americans) and 16% had a diastolic blood pressure of >90 (14% for whites and 20% for African Americans). During the 6 years of follow-up, 29% of the sample died (with no difference in mortality rates between whites and African Americans). PARTICIPANTS: 4,000 community-dwelling people age 65 years and older; 1,846 were white and 2,154 were African American. MEASUREMENTS: Systolic and diastolic blood pressure and all-cause mortality. RESULTS: Systolic blood pressure positively related to mortality during the 6 years of follow-up (relative risk = 1.05). Among whites the relationship of diastolic pressure to mortality was nonlinear, with those at the upper and lower ends of the distribution at increased risk. Among African Americans, diastolic pressure was unrelated to mortality. The analyses were controlled for age; gender; education; body mass index (BMI); smoking history; taking a medication to manage blood pressure; a history of cancer, diabetes mellitus, heart attack, or stroke; poor subjective health; impaired functional status; and cognitive impairment. CONCLUSIONS: The findings confirm that among older adults there is a significant relationship overall between systolic blood pressure and mortality over 6 years of follow-up in both whites and African Americans. Diastolic pressure was a risk factor for whites only.     

Application of national screening criteria for blood pressure and cholesterol to perimenopausal women: prevalence of hypertension and hypercholesterolemia in the Study of Women's Health Across the Nation

National screening guidelines for hypertension and cholesterol were applied to the multiethnic sample of perimenopausal women (N = 1349) in the Study of Women's Health Across the Nation (SWAN). To reduce low-density lipoprotein, lifestyle modification was indicated in 9.5% of patients and drug therapy in 5%. Chinese and Japanese women were least likely and African Americans were most likely to require interventions. Among all women, 27% were prehypertensive, 23% were hypertensive (blood pressure >140/90 mm Hg or treated), and 9.1% were untreated hypertensive. Untreated hypertension was lowest among Japanese and Chinese and highest among Hispanic and African-American women. Among all hypertensives, 60.5% were treated and only 58.5% of those treated were controlled. Control rates were lowest among African Americans and Hispanics. In this relatively low-risk population, a significant proportion of women with hypertension or hypercholesterolemia were either not treated, not treated adequately, or had borderline risk factors that would benefit from lifestyle interventions to prevent the need for future drug treatment.     

Tobacco and myocardial infarction in middle-aged women: a study of factors modifying the risk

BACKGROUND: Although myocardial infarction (MI) is strongly related to smoking, few have studied why some smokers are more vulnerable than others. This study explored how the risk of MI in current and former smokers is modified by other cardiovascular risk factors. METHODS: Incidence of MI (fatal and nonfatal) amongst 10619 women, 48.3 +/- 8.2 years old, were studied in relation to smoking, hypertension, hypercholesterolaemia, diabetes, marital status and occupational level over a mean follow-up of 14 years. RESULTS: Of the 3738 smokers, one-third had at least one major biological risk factor besides smoking; 228 women had MI during follow-up. Smoking and hypertension showed a synergistic effect on incidence of MI. The adjusted relative risks (RR) were 12.2 (95% CI: 7.5-19.8) for smokers with hypertension, 5.3 (CI:3.3-8.1) for smokers with normal blood pressure and 2.4 (CI:1.4-4.3) for never-smokers with hypertension (reference: normotensive never-smokers). The corresponding RRs for diabetic smokers and diabetic never-smokers were 19.0 (CI: 10.2-35.4) and 8.8 (CI: 4.4-17.4), respectively (reference: nondiabetic never-smokers). In terms of attributable risks, hypertension, hypercholesterolaemia and diabetes accounted for 12.9, 11.5 and 7.2%, respectively, of MI in female smokers. Low socio-economic level and being unmarried accounted for 19.6 and 1.6%, respectively. CONCLUSIONS: Although smoking is a major risk factor for MI, the risk varies widely between women with similar tobacco consumption. The results illustrate the need of a global risk factor assessment in female smokers and suggest that female smokers should be targets both for intensified risk factor management and programmes to stop smoking.     

Body mass index and the risk of stroke in men

BACKGROUND: Although obesity is an established risk factor for coronary heart disease, its role as a risk factor for stroke remains controversial. METHODS: Prospective cohort study among 21 414 US male physicians participating in the Physicians' Health Study. Incidence of total, ischemic, and hemorrhagic stroke was measured by self-report and confirmed by medical record review. We used Cox proportional hazards models to evaluate the association of body mass index (BMI), calculated as self-reported weight in kilograms divided by the square of the height in meters, with risk of total, ischemic, and hemorrhagic stroke. RESULTS: During 12.5 years of follow-up, 747 strokes (631 ischemic, 104 hemorrhagic, and 12 undefined) occurred. Compared with participants with BMIs less than 23, those with BMIs of 30 or greater had an adjusted relative risk of 2.00 (95% confidence interval [CI], 1.48-2.71) for total stroke, 1.95 (95% CI, 1.39-2.72) for ischemic stroke, and 2.25 (95% CI, 1.01-5.01) for hemorrhagic stroke. When BMI was evaluated as a continuous variable, each unit increase of BMI was associated with a significant 6% increase in the adjusted relative risks of total (95% CI, 4%-8%), ischemic (95% CI, 3%-8%), and hemorrhagic stroke (95% CI, 1%-12%). Additional adjustment for hypertension, diabetes mellitus, and hypercholesterolemia slightly attenuated the risks for total and ischemic (relative risk, 4%; 95% CI, 2%-7%), but not hemorrhagic, stroke. CONCLUSIONS: These prospective data indicate a significant increase in the relative risk of total stroke and its 2 major subtypes with each unit increase of BMI that is independent of the effects of hypertension, diabetes, and cholesterol. Because BMI is a modifiable risk factor, the prevention of stroke may be another benefit associated with preventing obesity in adults.     

The association between hypertension and other cardiovascular risk factors in young adult African Americans

Hypertension is a major cause of cardiovascular disease in African Americans. The excess morbidity and mortality due to cardiovascular disease in African Americans compared to Caucasians is not well explained. The purpose of this study was to examine the association between hypertension and other cardiovascular risk factors in young adult African Americans. A risk factor scoring system was developed, based on national guidelines for obesity, smoking, cholesterol levels, glucose tolerance, and blood pressure. Data from a previously studied cohort of 206 women and 117 men were analyzed for the association of hypertension with other risk factors. Among women, risk factor intensification is due to impaired glucose tolerance and obesity. Among men, intensification appears to be related to all major risk factor categories. These findings indicate that among hypertensive African Americans there is an amplification of other risk factors. The data also support the clinical management of multiple risk factors as well as the achievement of blood pressure control.     

Diabetes-related comorbidities in Asian Americans: results of a national health survey

OBJECTIVE: The aim of this study was to compare the prevalence of diabetes-related comorbidities in Asian Americans to the prevalence in other racial and ethnic groups in the United States using data from the 2001 Behavioral Risk Factor Surveillance System (BRFSS). METHODS: The BRFSS is a population-based telephone survey of the health status and health behaviors of 212,510 Americans aged > or = 18 years in all 50 states, Guam, Puerto Rico, and the U.S. Virgin Islands. In 2001, participants included 196 Asian Americans, 1138 African Americans, 1276 Hispanics, 294 Native Americans, 71 Pacific Islanders, and 7799 non-Hispanic Whites with a self-reported physician diagnosis of diabetes. Comorbidity was determined by self-report. Odds ratios (OR) were adjusted for age, sex, body mass index (BMI) or height and weight, duration of diabetes, smoking, and health-insurance status. RESULTS: The adjusted prevalences of hypercholesterolemia and retinopathy were similar across groups. Relative to Asian Americans, only African Americans were more likely to report hypertension [adjusted OR=2.1, 95% confidence interval (CI)=1.0-4.2, P<.05]. Higher odds of current or past foot ulceration was observed for Hispanics (adjusted OR=2.8, 95% CI=1.2-6.9), Native Americans (adjusted OR=4.2, 95% CI=1.4-12.8), and Pacific Islanders (adjusted OR=7.4, 95% CI=1.3-41.2) compared with Asian Americans. CONCLUSIONS: Among Americans with diabetes, Asian Americans have a prevalence of hypertension, hypercholesterolemia, retinopathy, and foot ulceration that is similar to that in Whites. Asian Americans had a significantly lower prevalence of hypertension than African Americans did and a lower prevalence of foot ulceration than Hispanics, Native Americans, and Pacific Islanders did.     

Prevalence of heart disease and stroke risk factors in persons with prehypertension in the United States, 1999-2000

BACKGROUND: Recent guidelines classify persons with above-optimal blood pressure (BP) but not clinical hypertension as having prehypertension. METHODS: Data were analyzed for 3488 persons aged 20 years and older with BP measured in the 1999-2000 National Health and Nutrition Examination Survey. The prevalence of risk factors-above-normal (> or =200 mg/dL [> or =5.17 mmol/L]) and high (> or =240 mg/dL [> or =6.21 mmol/L]) total cholesterol levels, diabetes mellitus, current smoker, and overweight or obesity-and the number of risk factors present were compared among BP groups (normotension, prehypertension, and hypertension). Multivariable logistic regression included age, sex, and race/ethnicity as covariates. RESULTS: Overall, 39% of persons were normotensive,31% were prehypertensive, and 29% were hypertensive. The age-adjusted prevalence of prehypertension was greater in men (39.0%) than in women (23.1%). African Americans aged 20 to 39 years had a higher prevalence of prehypertension (37.4%) than whites (32.2%) and Mexican Americans (30.9%), but their prevalence was lower at older ages because of a higher prevalence of hypertension. The probabilities of above-normal cholesterol levels, overweight/obesity, and diabetes mellitus were greater for persons with prehypertension vs normotension, whereas the probability of currently smoking was lower. Persons with prehypertension were 1.65 times more likely to have at least 1 other adverse risk factor than were those with normotension (P<.001). Among participants with prehypertension, there were no significant race/ethnic or sex differences in the likelihood of having at least 1 other risk factor. CONCLUSIONS: The greater prevalence of risk factors in persons with prehypertension vs normotension suggests the continued need for early clinical detection and intervention of prehypertension and comprehensive preventive and public health efforts.     

Sexual Risk Intervention In Multiethnic Drug And Alcohol Users

An estimated 38.6 million persons globally are living with HIV, of whom over 1.1 million reside in Zambia. Of the 2 million cases in the US, 64% of new cases among women are among African Americans. Alcohol and drug use represents a significant risk factor for HIV transmission among both Zambians and African Americans. In addition, gender dynamics in both the US and Zambia promote transmission. This study examines two interventions targeting HIV risk behavior among HIV positive substance users, women in Miami, USA (the New Opportunities for Women (NOW) Project) and men in Lusaka, Zambia (the Partner Project). The study compares the efficacy of these two culturally tailored sexual behavior interventions provided in group and individual session formats. US and Zambian participants increased sexual barrier use and reduced substance-related sexual risk. Comparatively greater gains were made by higher risk Zambian males than US females in both group and individual conditions. Among lower risk participants, women in the group condition achieved and sustained the greatest comparative risk reductions. Results suggest that cost effective group HIV transmission risk reduction interventions for multiethnic individuals can be successfully implemented among both female and male drug and alcohol users in multinational settings.     

辛伐他汀对血脂异常人群缺血性脑卒中的预防

目的研究辛伐他汀对血脂异常人群缺血性脑卒中的预防作用。方法将2853例血脂异常人群分为预防组(693例)和对照组(2160例),预防组给予辛伐他汀20mg/d,睡前口服。分析2组血脂变化、心脑血管事件、脑卒中等差异。结果预防组受试者糖尿病患病率比对照组高,预防组随访率98．7%,对照组随访率96．2%。预防组低密度脂蛋白胆固醇较对照组低[(2．54±1．01)mmol/L vs(4．12±1．29)mmol/L,P＜0．05],5年生存率高(94．13% vs 83．47%,P＜0．01),缺血性脑卒中和心脑血管事件发生率低。2组死亡的主要原因是:心脑血管疾病、肿瘤和感染。吸烟、高血压、肥胖和糖尿病是脑卒中和心脑血管事件的高危因素。结论辛伐他汀能有效降低血脂异常人群的心脑血管事件。     

Risk factors for coronary atherosclerosis in the elderly

To determine the importance of traditional risk factors for coronary artery disease (CAD) in the elderly, the authors studied 64 consecutive patients with angiographically normal or near-normal coronary arteries and 64 patients with CAD. All patients were greater than or equal to sixty years old. The risk factors studied were male sex, hypertension, diabetes mellitus, hypercholesterolemia, cigarette smoking, sedentary life-style, and family history. The prevalence of these risk factors in the two groups of patients was compared. The results suggest that in persons greater than or equal to 60 years old, male sex and cigarette smoking continue to remain risk factors for CAD. Since most of the patients with diabetes and hypertension were on medical management for their condition, the authors' findings also suggest that diabetes mellitus, even under treatment, remains an important risk factor for CAD in the elderly but controlled hypertension does not. Other traditional risk factors (hypercholesterolemia, sedentary life-style, and family history) do not discriminate individuals with moderate to severe CAD from those with normal or near-normal coronary arteries in persons greater than or equal to sixty years old.     

Cardiac risk factors: still important in the elderly

Shown to be associated with new coronary events in elderly men and women are cigarette smoking, systolic or diastolic hypertension, hypercholesterolemia, low serum HDL cholesterol, increased ratio of serum total cholesterol to serum HDL cholesterol, hypertriglyceridemia, diabetes mellitus, obesity, physical inactivity, increased age, prior coronary artery disease, and electrocardiographic and echocardiographic left ventricular hypertrophy. The greater the number of major coronary risk factors, the higher the incidence of new coronary events. Risk factor modification should therefore be considered in elderly persons.     

Recognition and Management of Hypertension in Older Persons: Focus on African Americans

Hypertension is the most commonly diagnosed condition in persons aged 60 and older and is the single most important risk factor for cardiovascular disease (ischemic heart disease, heart failure, and stroke), kidney disease, and dementia. More than half of individuals with hypertension in the United States are aged 60 and older. Hypertension disproportionately affects African Americans, with all age groups, including elderly adults, having a higher burden of hypertension‐related complications than other U.S. populations. Multiple clinical trials have demonstrated the beneficial effects of blood pressure (BP) reduction on cardiovascular morbidity and mortality, with most of the evidence in individuals aged 60 and older. Several guidelines have recently been published on the specific management of hypertension in individuals aged 60 and older, including in high‐risk groups such as African Americans. Most recommend careful evaluation, thiazide diuretics and calcium‐channel blockers for initial drug therapy in most African Americans, and angiotensin‐converting enzyme inhibitors and angiotensin receptor blockers in those with chronic kidney disease or heart failure. Among the areas of controversy is the recommended target BP in African Americans aged 60 and older. A recent U.S. guideline recommended raising the systolic BP target from less than 140 mmHg to less than 150 mmHg in this population. This article will review the evidence and current guideline recommendations for hypertension treatment in older African Americans, including the rationale for continuing to recommend a SBP target of less than 140 mmHg in this population.     

Pathogenesis of hypertension in African Americans

Hypertension is a compelling disease process that disproportionately affects African Americans. It is the single largest risk factor for cardiovascular disease in African Americans. The end organ manifestations of hypertension are striking and include higher rates of stroke, significantly increased renal disease including end-stage renal disease requiring dialysis, higher risk of left ventricular hypertrophy, and an associated higher risk of heart failure. The cause of these more aggressive end organ phenomena is likely multifactorial and includes a mix of genetic and environmental influences. Intriguing polymorphisms of the epithelial sodium channel are consistent with patterns of hypertension seen in African Americans. Obesity, especially in African-American women, may be closely related to hypertension as a result of sympathetic nervous system stimulation.     

老年高血压病患者左心室肥厚与脑白质疏松症的关系

目的　探讨老年高血压病患者左心室肥厚和脑白质疏松症 (LA)的关系。方法　 13 8例老年高血压病患者 ,按有或无LA分为两组 ,并对其年龄、是否合并左心室肥厚、糖尿病、高胆固醇血症、吸烟史以及收缩压和舒张压水平、高血压病持续时间进行分析。结果　在单因素Logistic回归分析中 ,左心室肥厚、收缩压水平、高血压病持续时间及年龄均为LA的影响因素 ;在多因素条件Logistic回归分析中 ,左心室肥厚仍为LA的危险因素之一 (OR =2 .771,95 %CI值 1.2 60～6.0 94;P <0 .0 1)。结论　左心室肥厚为老年高血压病患者LA独立的危险因素。     

Coronary heart disease in African Americans

African Americans have the highest overall mortality rate from coronary heart disease (CHD) of any ethnic group in the United States, particularly out-of-hospital deaths, and especially at younger ages. Although all of the reasons for the excess CHD mortality among African Americans have not been elucidated, it is clear that there is a high prevalence of certain coronary risk factors, delay in the recognition and treatment of high-risk individuals, and limited access to cardiovascular care. The clinical spectrum of acute and chronic CHD in African Americans is similar to that in whites. However, African Americans have a higher risk of sudden cardiac death and present more often with unstable angina and non-Q-wave myocardial infarction than whites. African Americans have less obstructive coronary artery disease on angiography, but may have a similar or greater total burden of coronary atherosclerosis. Ethnic differences in the clinical manifestations of CHD may be explained largely by the inherent heterogeneity of the coronary syndromes, and the disproportionately high prevalence and severity of hypertension and type 2 diabetes in African Americans. Identification of high-risk individuals for vigorous risk factor modification-especially control of hypertension, regression of left ventricular hypertrophy, control of diabetes, treatment of dyslipidemia, and smoking cessation--is key for successful risk reduction.     

Stroke following acute myocardial infarction in diabetics.

To investigate the effect of diabetes on stroke after myocardial infarction (MI), we studied consecutive MI patients admitted to the coronary-care unit prospectively, and compared diabetics with non-diabetics. Seven per cent (11/148) of diabetics and 3% (8/297) of non-diabetics had a stroke within 1 month after MI (P = 0.020). Previous stroke and hypertension were significant risk factors for stroke after MI in diabetics, but there were no significant risk factors in non-diabetics. Hypertension was more frequent in diabetics with (12/14; 86%) than in diabetics without (63/134; 47%) a previous stroke (P less than 0.025). Severe hypotension was more frequent in diabetics (9/11) than in non-diabetics with stroke after MI (0/8) (P = 0.002). We conclude that hypertension is a risk factor for stroke after MI in diabetics, and that may be at risk for hypotensive stroke after MI. Stroke after MI may be more frequent in diabetics than in non-diabetics.     

Diabetes mellitus as a risk factor for stroke incidence and mortality in Mexican American older adults

BACKGROUND: Little is known regarding diabetes mellitus as a risk factor for stroke incidence and death in older Mexican Americans. The authors studied diabetes and other potential risk factors for stroke in a sample of community-dwelling older Mexican Americans. METHODS: A prospective cohort design was used that involved the Hispanic Established Population for the Epidemiologic Study of the Elderly, a longitudinal study using a weighted probability sample of Mexican Americans (aged older than 65 years) living in the southwestern United States. 3050 older Mexican American persons were originally interviewed and tested at baseline and then followed with reassessment at 2, 5, and 7 years. The incidence of stroke and stroke death were studied for the participants during a 7-year follow-up period. RESULTS: 690 participants were identified at baseline with diabetes. 238 participants experienced a first-time stroke during the follow-up period. 66 died as a result of a stroke. Cox proportional hazard regression analysis revealed an increased hazard ratio (HR) for stroke in persons with diabetes (HR, 1.80; 95% confidence interval [CI], 1.32 to 2.44; p <.0002) when adjusted for age, sex, body mass index, smoking, systolic blood pressure, previous heart attack, and lower extremity function. The stroke mortality rate was also higher (HR, 2.02; 95% CI, 1.04 to 3.93) for persons with diabetes when adjusted for covariates. CONCLUSION: Diabetes was associated with an increased incidence of stroke and death in older Mexican Americans, particularly those taking insulin.     

Clinical Assessment and Rest and Stress Echocardiography for Prediction of Long-Term Prognosis in African Americans with Known or Suspected Coronary Artery Disease

Background: There is limited information on noninvasive risk stratification of African Americans, a high-risk group for cardiovascular events. We investigated the value of clinical assessment and echocardiography for the prediction of a long-term prognosis in African Americans. Methods: Dobutamine echocardiography was performed in 324 African Americans. Two-dimensional measurements were performed at rest, and rest and stress wall motion was assessed. A retrospective follow-up was conducted for cardiac events: myocardial infarction (MI) or cardiac death (CD). Results: The mean age was 59 ± 12 years, and 83% of patients had hypertension. The follow-up was obtained in 318 (98%) patients for a mean of 5.3 years. The events occurred in 107 (33%) subjects. The independent predictors of events were history of MI (P = 0.001, risk ratio [RR] 2.04), ischemia (P = 0.007, RR 1.97), fractional shortening (P = 0.033, RR 0.08), and left atrial (LA) dimension (P = 0.034, RR 1.39). An LA size of 3.6 cm and a fractional shortening of 0.30 were the best cutoff values for the prediction of events. Prior MI, ischemia, LA size >3.6 cm, and fractional shortening <0.30 were each considered independent risk predictors for events. The event rates were 13%, 21%, 38%, 59%, and 57% in patients with 0, 1, 2, 3, and 4 risk predictors, respectively. Event-free survival progressively worsened with an increasing number of predictors: 0 or 1 versus 2 predictors, P < 0.001; 2 versus 3 or 4 predictors, P = 0.003. Conclusion: The long-term prognosis of African Americans can be accurately predicted by clinical assessment combined with rest and stress echocardiography.     

Low Birth Weight Contributes to the Excess Prevalence of End-Stage Renal Disease in African Americans

The risk of hypertension and related target organ damage is much greater in African Americans than in Caucasians. The risk of hypertensive end-stage renal disease is approximately five-fold higher in African Americans. Many studies have shown that low birth weight is strongly associated with increased risk of hypertension, stroke, and myocardial infarction. However, until recently the relationship between birth weight and hypertension-related diseases was not clearly established in African Americans. Moreover, it was also unclear if low birth weight in humans heightened the risk for end-stage renal disease. This is a critical gap in the literature, since low birth weight occurs at twice the rate in African Americans as among Caucasians. We identified a significant relationship between end-stage renal disease and low birth weight in both African Americans and Caucasians. Given the higher rates of low birth weight in African Americans, differences in fetal development may, therefore, contribute to the racial disparity in end-stage renal disease. Continued study of the biological factors linking early development with later risk of hypertension-related diseases is important and may shed light on racial disparities in health outcomes.