What We Know From the Biggest Study of Heart Health in Blacks

Montoya Taylor, M.D., attended medical school at Brown University in the mid-2000s and heard a lot about an influential study in the small town of Framingham, Massachusetts. Now spanning three generations of mostly white participants, the Framingham Heart Study is largely responsible for the current understanding of cardiovascular risks.
But Dr. Taylor made sure his classmates knew about a lesser-known but equally important study that was under way in his home state of Mississippi—the Jackson Heart Study.
Launched in 1998, it’s the largest research project looking at the causes of cardiovascular disease in African Americans, which investigators say has earned it the nickname “Framingham of blacks.”
The Framingham study has been “great for [understanding cardiovascular disease in] Caucasians, but it doesn’t really translate to African Americans, Latinos, Native Americans and other populations,” said Dr. Taylor, an interventional cardiologist who as an undergraduate student was involved in research in the early years of the Jackson Heart Study.
Data from the Jackson Heart Study has shown African Americans—the second-largest racial group in the United States after whites—are affected differently by risk factors for heart disease and stroke. For example, African Americans tend to have much higher blood pressure readings at night compared to other races and ethnic groups, and their blood pressure doesn’t drop as it should during sleep.
“The challenge is, how do you diagnose and monitor hypertension in a high-risk population like African Americans,” said study director and principal investigator Adolfo Correa, M.D., a professor of medicine and pediatrics at the University of Mississippi Medical Center. “That’s pretty important to know because of the number of African Americans that are walking around with undiagnosed and untreated hypertension.”
Among African-American adults, 43 percent have high blood pressure compared with 29 percent of white adults, and nearly 60 percent don’t have it under control, according to the Centers for Disease Control and Prevention.
Researchers are also finding that sickle cell disease, an inherited blood disorder that predominantly affects African Americans and can increase the risk of stroke, may need to be treated differently in people who also have diabetes.
A recent study that included participants from the Jackson Heart Study found that diabetes tests in African Americans with sickle cell disease may not accurately reflect their blood sugar levels. The readings may be lower because the life span of the red blood cells may be shortened, the authors wrote.
Researchers say the federally funded study was long overdue by the time more than 5,000 participants were recruited in the Jackson, Mississippi, area nearly two decades ago. Roughly a fifth have since died, leaving about 4,000 participants between the ages of 35 and 84.
Jermal Clark is taking part in the study. The 65-year-old businessman said he is old enough to remember when African Americans who needed emergency care languished in hospital waiting rooms because white patients were given priority.
He signed up because “the evidence that is found can be utilized for future African Americans—or future anybody. Medicine is not based on one group of people.”
Clark said he’s always exercised regularly and had a diet rich in fruits and vegetables. But he’s more vigilant about his health since joining the study and encourages others to do the same.
The study is overseen by Jackson State University, Tougaloo College and the University of Mississippi Medical Center. Participants have had three clinic visits over the past 17 years and each year provide updates on their health by phone.
All that data is then used by researchers who can analyze it and figure out what it all means.
The data has allowed scientists to study how discrimination, poverty, education and income affect the cardiovascular health of African Americans, and whether African Americans have a genetic predisposition to certain conditions and diseases.
“It’s not just about lifestyle,” said Wendy White, deputy director of the study’s undergraduate training center at Tougaloo College. “There are other things that we need to know about cardiovascular disease [in African Americans].”
But although researchers know a lot more about cardiovascular health in African Americans, more studies are needed that delve into the relationship between risk factors and how to best treat those conditions in African Americans, Dr. Correa said.
For some of the Jackson Heart investigators, their role is beyond that of scientist. White and others are participants. So is White’s husband and other colleagues’ family members.
For Dr. Taylor, his time at the study’s undergraduate training center more than 15 years ago altered his medical career path. His interest switched from oncology to cardiology. And last year, after more than a decade away, Dr. Taylor moved back to Mississippi to work at the University of Mississippi Medical Center.
“It’s one of the most rewarding experiences that I would say an individual can have,” Dr. Taylor said of being able to care for his fellow Mississippians.
But with the joy also sometimes comes the sadness when a life can’t be saved, he said, because “I’m sure if I was to dig a little deep into people’s connections, I could probably find those six degrees of separation.”
From American Heart Association News