Young and healthy African-American men have higher central blood pressure and their blood vessels are stiffer compared to their white counterparts, signs that the African American men are developing hypertension early and with little outward sign, according to a new study. While the study found that central blood pressure -- the pressure in the aorta, near the heart -- was higher in the African-American men, the study found no difference in brachial blood pressure -- measured on the arm -- between the two groups.
Taken together, the findings suggest that hypertension (high blood pressure) may be developing undetected in young African-American men and that measuring central blood pressure may be a better means of detecting the problem as it develops.
"Central blood pressure holds greater prognostic value than conventional brachial blood pressure as central pressure more aptly reflects the load encountered by the heart," the authors explained. "Thus, brachial blood pressure may neglect important information on cardiovascular burden and response to therapy in African-American men."
The study, "Racial differences in central blood pressure and vascular function in young men" was carried out by Kevin S. Heffernan, Sae Young Jae, Kenneth R. Wilund, Jeffrey A. Woods and Bo Fernhall, at the University of Illinois, Urbana-Champaign. The study appears online in the American Journal of Physiology-Heart and Circulatory Physiology, published by The American Physiological Society. Dr. Heffernan has since moved to Tufts Medical Center in Boston. Dr. Jae is also affiliated with the University of Seoul.
African-American men have higher levels of hypertension than white men. Hypertension is known as the silent killer because it can develop without the individual knowing it. According to the U.S. Centers for Disease Control and Prevention, hypertension is a major risk factor for heart disease, stroke, congestive heart failure, and kidney disease. In 2002, hypertension was listed as a primary or contributing cause of death for 277,000 Americans.
The University of Illinois researchers hypothesized that the blood vessels of the black men would show greater dysfunction than the white men, even though both groups were young and equally healthy and fit. The vascular damage they looked for included stiffening and thickening of the blood vessels. These conditions result in pulsatile (not smooth) blood flow (and at higher pressure) to organs. The pressure can damage the organs over time.
Both groups healthy
The study included 55 young men, 30 white and 25 African-American. Most were university seniors. The average age was 23. There were no differences between the groups on a variety of measures, including heart rate, cardiorespiratory fitness, body mass index, body fat, blood lipids and glucose levels.
The researchers measured vascular function in a variety of ways, including:
- aortic blood pressure and stiffness
- brachial blood pressure
- carotid artery blood pressure
- carotid artery thickness and stiffness
They found the African-American men had similar brachial blood pressure, compared to the white men, but they had significantly higher:
- Central blood pressure, a measure of the pressure found in the artery, near the heart. The researchers used an instrument that takes blood pressure at the wrist and then calculates the central blood pressure.
- Carotid artery pressure. The carotid artery runs through the neck.
The African-American men, unlike the white men, also showed signs of early vascular damage that could lead to hypertension. For example, they had:
- Thicker carotid arteries, a sign of vascular damage that is usually found in older individuals and associated with atherosclerosis.
- Stiffer arteries, which are associated with high blood pressure. When the heart beats, blood flows through stiff arteries at greater speed and pressure. Elastic arteries provide a smoother blood flow and help prevent damage to organs receiving the blood and place less stress on the heart.
- Less change in diameter of the arteries when the heart beats, another measure of vascular stiffness. A healthy artery is more elastic will change in size as the blood flows through with each beat of the heart.
"Although having a similar cardiovascular risk factor profile as young white men, diffuse macrovascular and microvascular dysfunction is present at a young age in apparently healthy African American men," the authors wrote. "Values seen are comparable to values often reported in older individuals or individuals with more advanced hypertensive disease," they said.
These results do not shed light on why this happens to young and fit African-American men, Heffernan said. There may be environmental differences, such as differences in diet, which were not examined as part of this study, he said.
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American Physiological Society. "Hypertension Develops Early, Silently, In African-American Men." ScienceDaily. ScienceDaily, 25 November 2008. <www.sciencedaily.com/releases/2008/11/081117082046.htm>.
American Physiological Society. (2008, November 25). Hypertension Develops Early, Silently, In African-American Men. ScienceDaily. Retrieved March 12, 2018 from www.sciencedaily.com/releases/2008/11/081117082046.htm
American Physiological Society. "Hypertension Develops Early, Silently, In African-American Men." ScienceDaily. www.sciencedaily.com/releases/2008/11/081117082046.htm (accessed March 12, 2018).
Heart disease is the No. 1 killer for all Americans, and stroke is also a leading cause of death. As frightening as those statistics are the risks of getting those diseases are even higher for African-Americans.
The good news is, African-Americans can improve their odds of preventing and beating these diseases by understanding the risks and taking simple steps to address them.
“Get checked, then work with your medical professional on your specific risk factors and the things that you need to do to take care of your personal health,” said Winston Gandy, M.D., a cardiologist and chief medical marketing officer with the Piedmont Heart Institute in Atlanta and a volunteer with the American Heart Association.
High blood pressure, obesity and diabetes are the most common conditions that increase the risk of heart disease and stroke. Here’s how they affect African-Americans and some tips to lower your risk.
High Blood Pressure
The prevalence of high blood pressure in African-Americans is the highest in the world. Also known as hypertension, high blood pressure increases your risk of heart disease and stroke, and it can cause permanent damage to the heart before you even notice any symptoms, that's why it is often referred to as the "silent killer." Not only is HBP more severe in blacks than whites, but it also develops earlier in life.
Research suggests African-Americans may carry a gene that makes them more salt sensitive, increasing the risk of high blood pressure. Your healthcare provider can help you find the right medication, and lifestyle changes can also have a big impact.
“You can’t do anything about your family history, but you can control your blood pressure,” Dr. Gandy said.
If you know your blood pressure is high, keeping track of changes is important. Check it regularly, and notify your doctor of changes in case treatment needs to be adjusted, Dr. Gandy said. Even if you don’t have high blood pressure, he recommends checking it every two years.
“The No. 1 thing you can do is check your blood pressure regularly,” he said.
African-Americans are disproportionately affected by obesity. Among non-Hispanic blacks age 20 and older, 63 percent of men and 77 percent of women are overweight or obese.
If you’re carrying extra weight, Dr. Gandy suggests focusing on the quality of your diet throughout the day, not just during mealtime.
“You can add hundreds of calories to your diet just on snacking,” he said. Choosing wise snacks can be part of a healthy diet.
Dr. Gandy knows all too well how challenging it can be to lose weight. After years of prescribing diet changes for his patients, he decided it was time to follow his own advice by walking at least 30 minutes a day and eliminating sugary drinks and desserts. The hard work paid off. Dr. Gandy lost 25 pounds in six months and feels much better.
He also suggests limiting red meat in favor of lean meats such as chicken or fish, and watching portions on carbohydrate-heavy foods, such as pasta and rice. Look for whole grain options instead.
“Make vegetables the main part of the meal and fill up with those rather than other foods,” he said.
Dr. Gandy cautioned that even things that are healthy can pack in calories.
“If you’re thirsty, drink water, not juice,” Dr. Gandy said.
African-Americans are more likely to have diabetes than non-Hispanic whites.
Diabetes is treatable and preventable, but many people don’t recognize early warning signs. Or, they avoid seeking treatment out of fear of complications.
Dr. Gandy said many people associate the disease with older relatives who were diagnosed too late or had poorly-controlled diabetes and suffered preventable complications such as blindness, amputations, or renal failure.
For diabetes and other heart disease risks, regular exercise also plays a key role – both in strengthening the cardiovascular system and burning extra calories.
Aim for at least 30 minutes of walking a day, Dr. Gandy said.
“That’s enough to get the heart rate up,” he said. “There’s no need to do a marathon.”
This content was last reviewed July 2015.