Hypertension risk for “race-aware” black Americans

JOHNS HOPKINS (US) — African Americans who think more about racial concerns have higher blood pressure than those who don’t, according to new research.

The findings could help explain the disproportionately high rate of hypertension in black Americans, who have the highest prevalence of any group in the United States and one of the highest rates in the world.

“A preoccupation with race among blacks leads to hyper-vigilance, a heightened awareness of their stigmatized status in society and a feeling that they need to watch their backs constantly,” says Lisa A. Cooper, professor of medicine at the Johns Hopkins University School of Medicine and senior author of the study, published in the American Journal of Hypertension.

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“African Americans have higher blood pressure and it has been difficult to explain why this is true,” Cooper says. “It doesn’t appear to be genetic, and while things like diet, exercise, and reduced access to health care may contribute, we think that a tense social environment, the sense of being treated differently because of your race, could also possibly explain some of what’s behind the higher rates.”

Hyper-vigilance and race consciousness have drawn more public attention in the wake of the killing in Florida of Trayvon Martin, an unarmed black teenager, in a confrontation with an armed neighborhood watch volunteer, Cooper says. Her own African-American son, she says, is very aware of his surroundings.

“It’s stressful for him to walk around thinking at any time someone might think he’s dong something wrong just because of his race,” she says. “That’s just something he lives with. If you don’t live with it, maybe it’s hard to understand it. It’s something people often don’t want to talk about.”

As part of ongoing research into doctor-patient relationships and racial disparities, Cooper and her colleagues surveyed 266 patients in urban health clinics in Baltimore between 2003 and 2005. Sixty-two percent of the patients were black. To test for race consciousness, they used the 2002 Behavioral Risk Factor Surveillance System “Reactions to Race” module developed by the US Centers for Disease Control and Prevention. Patients—both black and white—were asked how often they thought about their race.

Two categories were created: Those who said if they ever think about their race and those who said they never do. Half of the black patients responded that they “ever” think about it, and one in five white patients says they did.

When blood pressures were measured, race-conscious black patients had on average significantly higher diastolic blood pressure (roughly 5 millimeters of mercury) and somewhat higher systolic blood pressure (some 4 millimeters of mercury) than black patients who did not think about their race. There was no such effect on blood pressure in race-conscious white patients.

Systolic blood pressure, the top number in a blood pressure reading, measures the force that pressure from the beating heart places on the arteries. Diastolic blood pressure, the bottom number, indicates the pressure in the arteries when the heart rests between beats.

Cooper, director of the Johns Hopkins Center to Eliminate Cardiovascular Health Disparities, says it is well known that chronic stress can increase blood pressure. Similarly, she says tasks that require active coping efforts may increase heart rate and systolic blood pressure, while tasks that require quiet attentiveness and vigilance may lead to decreased cardiac output as well as increased diastolic blood pressure.

Cooper notes that it can be stressful for black people to go shopping in a store and feel they are being watched extra closely. Equally stressful, she says, is for example, waiting a long time to be served at a restaurant and being ignored, possibly because of one’s race.

More research is needed to understand the biological consequences of race consciousness, including those related to stress, she adds, with a goal of developing interventions to help people effectively cope with environmental stressors.

“We need to help people of all races cope with race-related stress in a healthier way,” she says.

The National Heart, Lung and Blood Institute funded the study.

Source: Johns Hopkins University