Black Americans are at greater risk of developing high blood pressure (hypertension) than Caucasians or other racial groups. Although researchers do not know the exact reason for this finding, they point out that black Americans tend to have an unusually high number of risk factors for high blood pressure. These risk factors include diabetes, high stress levels and increased salt intake and sensitivity.
There are other reasons that might help explain why black Americans are both at greater risk for high blood pressure, and once diagnosed with high blood pressure, at greater risk for complications. Studies have consistently shown that lower socioeconomic status, coupled with a high-fat and low potassium diet, is an important risk factor for high blood pressure. In addition, there may be genetic factors that factor into the equation. For example, researchers have learned that black Americans with the same blood pressure as white Americans tend to have enlarged left ventricles, compared to their white counterparts. In addition, hypertensive black Americans appear to be at much greater risk for kidney failure than white Americans, even after all the important variables are taken into account.
Because of the life-threatening complications of high blood pressure (stroke, heart failure, kidney failure), black Americans are urged to get their blood pressure checked – especially if high blood pressure runs in the family.
Prevalence in black Americans
In contrast with both black Africans and white Americans, black Americans are more likely to be diagnosed with high blood pressure (hypertension). Some studies have suggested that hypertension is present in as many as 40 percent of the black American community, where some researchers are labeling it an “epidemic.” Black Americans also tend to be younger when diagnosed and to have more severe hypertension than white Americans. They are also less likely to be able to control their high blood pressure than white Americans. As a result, black Americans are at particularly high risk of hypertension-related complications, such as:
Stroke. High blood pressure is a major risk factor for stroke, a condition in which the blood supply to the brain is disrupted, either by bleeding into the brain (hemorrhagic stroke) or blocked by a blood clot (ischemic stroke). Therefore, people of all races are at greater risk of a fatal stroke if they have high blood pressure. However, the risk for black Americans is a full 80 percent higher than among other Americans.
Death from heart disease. Hypertension causes the heart to work harder to pump blood through narrowed arteries in the body, which could lead to heart failure or contribute to coronary artery disease or heart attack. In fact, hypertension is the leading cause of heart failure among black Americans. Black American men are twice as likely as white men to die of heart failure, and black American women are almost three times as likely as white women to die of heart failure. Black Americans – especially black American women – are less likely to survive a heart attack than white Americans.
Kidney failure. Hypertension can affect the arteries that supply oxygen-rich blood to the kidneys, contributing to kidney failure. Among black Americans, the leading cause of partial or complete kidney failure is believed to be poorly controlled high blood pressure. In fact, African American are eight times more likely to develop kidney failure than white Americans and the risk of end-stage renal disease (ESRD) from hypertension is three times greater among black Americans than other Americans.
Blindness. Hypertension can damage the arteries that supply oxygen-rich blood to the eyes. Those fragile arteries can burst, causing vision problems or even blindness. Blindness can also result if the retina detaches from the rest of the eye. Eye damage due to hypertension has an incidence in black Americans twice that of white Americans.
Risk factors for black Americans
Black Americans have more risk factors for high blood pressure (hypertension), than other racial groups. For example, black women are more likely than white women to be extremely overweight or obese and/or diabetic, both of which are among the risk factors for hypertension:
Overweight or obesity. The heavier people are, the greater their risk of disease. Obesity (more than 20 percent over one’s ideal weight or body mass index greater than 30) increases the risk of disease to high or even “extremely high” levels, but just being overweight is a serious risk factor, too. These statistics are particularly important for black American women, who are significantly more likely to be overweight than white women, white men or black American men. Research shows that more than two-thirds of all black American women are not getting enough exercise.
Diabetes. Perhaps because obesity is linked to both type 2 diabetes and hypertension, diabetics are more likely to have hypertension than nondiabetics. Black Americans are also more likely to be diabetic than white Americans are. In contrast with white women, black American women are about 50 percent more likely to have diabetes. Black American men are also more likely to have diabetes than white men.
High stress levels. Stress contributes to heart disease by elevating blood pressure, and studies have shown that people who are under stress are more likely to suffer from heart attacks, high blood pressure and other forms of disease.
Smoking. A major risk factor for hypertension – as well as lung cancer, breast cancer, heart disease and many other illnesses – is smoking. Although blacks and whites are currently smoking at about equal rates, black Americans tend to smoke particularly dangerous brands of cigarettes that are high in nicotine and tar. Furthermore, researchers have found that at least some tobacco companies are specifically targeting the black American community. One study found significantly more cigarette ads in three popular black American magazines than more general publications.
Excessive alcohol use. Studies have consistently found a link between alcohol use and elevated blood pressure, as well as irreversible heart failure (alcoholic cardiomyopathy).
Fat in the diet. A diet high in saturated fat contributes to obesity. There are a number of strategies for reducing the amount of fat in daily meals. In general, the goal is to eat a balanced, heart-healthy diet.
Salt sensitivity. After eating salt, people who are salt-sensitive tend to show elevations in blood pressure that can be quite dramatic. Salt sensitivity can be particularly dangerous in the United States, where the average person consumes at least nine grams of sodium per day, with many Americans eating more than 12 grams daily. (The body requires only about half a gram of sodium per day, and the American Heart Association recommends that people consume no more than 2.4 grams per day.) Research has shown that black Americans tend to be more salt-sensitive than white Americans, and as many as 80 percent of black Americans with high blood pressure may be salt-sensitive.
Diagnosis methods for high blood pressure
All people are urged to have their blood pressure checked regularly, especially if hypertension runs in the family. Even children can develop high blood pressure. A blood pressure check is a painless procedure in which the healthcare professional wraps a blood pressure cuff around the patient’s arm, tightens it and then slowly releases it while noting the patient’s blood pressure. Normal blood pressure measurements are as follows:
Age
Normal Blood Pressure Measurement (in millimeters of mercury)
Newborn
Up to 70/45
5
Up to 115/75
6 to 12
Up to 125/80
13 to 15
Up to 126/78
16 to 18
Up to 120/80
Over 18
Up to 120/80
(Prehypertension: 130/80)
(High blood pressure: 140/90)
Treatment options
Diuretics are among the most effective drugs available for controlling blood pressure, especially among black Americans, and they happen to be relatively inexpensive, too. For black Americans whose blood pressure does not respond to diuretics alone, studies have shown the benefits of combining diuretics with other blood pressure medications, such as ACE inhibitors or beta blockers. Neither ACE inhibitors nor beta blockers seem to be as effective for black Americans when taken alone. However, ACE inhibitors are effective among black Americans suffering from kidney failure or heart failure in addition to high blood pressure.
Other medications that may be prescribed include calcium channel blockers (which are more expensive but are effective if diuretics cannot be tolerated) and cholesterol-reducing drugs. To reduce the risk of stroke, anticoagulants or antiplatelets may also be prescribed because they help to prevent the formation of blood clots.
In addition to taking blood pressure medication, black American hypertensives are urged to reduce the amount of salt and fat in the diet. One strategy is to follow the DASH diet, named from a study called Dietary Approaches to Stop Hypertension (DASH). The study found that the diet was particularly helpful in controlling the blood pressure of black Americans.
The ideal blood pressure goal among black Americans is uncertain. Based on the results of the African American Study of Kidney Disease and Hypertension (AASK) study, the Hypertension in African Americans Working Group of the International Society on Hypertension in Blacks issued the following guidelines in 2003:
As with other racial groups, black Americans with uncomplicated high blood pressure should strive to reach a target of 140/80 mmHg.
A target of 130/80 mmHg should be considered for black Americans with diabetes, kidney disease, a history of heart attack or stroke, or elevated risk for coronary artery disease.
Besides medication and dietary intervention, a number of additional approaches are often recommended to help lower pressure:
Quitting smoking. This is perhaps the most important thing a smoker can do to promote his or her own health. Among many other side effects, smoking elevates blood pressure.
Losing weight. Loss of weight in the abdominal area can immediately reduce blood pressure and helps to reduce the size of the heart. It is desirable to aim for people with a body mass index of less than 25. Weight loss accompanied by salt restriction may allow mild hypertensives to reduce or eliminate the need for medication.
Eating a heart-healthy diet that is low in saturated fat. Cookbooks are available for people interested in cooking heart-healthy food. Dietitians are also available for personal counseling about diet.
Getting adequate amounts of potassium, magnesium and calcium. Adequate intake of these minerals is thought by some experts to be more helpful than reducing salt intake for reducing blood pressure.
Regular aerobic exercise. Exercising at least three to four times per week is helpful for regulating high blood pressure, keeping in mind that the regularity of the exercise is more important than the intensity of the workout. For example, studies have shown that Tai Chi (an ancient Chinese workout involving slow relaxing movements) may lower blood pressure almost as well as moderately intense aerobics.
Limiting alcohol use to one 6-ounce glass of wine per day, one 12-ounce beer or one 1-ounce shot of distilled spirits for women, or 1 to 2 drinks per day for men.
Limiting salt intake to 2,000 milligrams (2 grams) of sodium per day.
Using stress management techniques. Emotional factors may play important roles in the development of hypertension. Studies have shown that cognitive-behavioral therapy, transcendental meditation, active religious faith and participation in church-related activities have all been associated with reducing blood pressure to healthy levels. (Watching or listening to religious services on radio or TV had no effect.)
Having a pet may also lower blood pressure.
Women are also encouraged to discuss with a physician any increased risk of hypertension as a result of taking birth control pills, particularly if over the age of 35.
Questions for your doctor
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to high blood pressure in black Americans:
How high is my blood pressure?
What are some immediate steps I can take to lower my blood pressure?
What other risk factors for heart disease do I have? Should we measure all of my risk factors?
What is my risk for kidney disease, blindness, heart failure and other complications of high blood pressure?
Should I be taking blood pressure-lowering medications? Which ones? At what dose?
What resources are there to learn about healthy lifestyle decisions?
Can I start an exercise program? What's an appropriate level of exercise?
If there are any genetic causes of high blood pressure, should my relatives also be checked?
How long will I have to take medication?
If I lower my blood pressure, will it lower the risk of serious complications?
