A nurse takes her patient's blood pressure.

Jackson Heart Study: Largest investigation of heart disease in African-Americans promises to pave way to better health

It is the most sweeping—and significant—study ever of cardiovascular disease in African-Americans. Now experts with the groundbreaking Jackson Heart Study (JHS) are taking stock of some of the many insights gleaned since the study began in 2000. They are insights researchers say will go a long way toward helping boost the long-term health of a group marked by a stubbornly high rate of heart disease compared to the rest of the population. Heart disease is the No. 1 cause of death for all Americans and almost half of African-Americans have some form of cardiovascular disease (which includes heart disease, stroke, and high blood pressure). Approximately 1 in 4 African-American males and females dies of heart disease. 

The 17-year-long observational study follows the health of about 5,300 African-Americans in the Jackson, Mississippi metropolitan area. It is comparable in scope to the Massachusetts-based Framingham Heart study, started in the 1948, except those participants are mainly white. The National Heart, Lung, and Blood Institute (NHLBI) and the National Institute on Minority Health and Health Disparities (NIMHD), which fund Jackson Heart, are continuing to explore the reasons behind the troubling disparities in heart health. Here are some of the more recent findings emerging from the JHS:   

1. A gene defect doubles the risk of heart disease. African-Americans with a gene called APOL1 carry a greater risk for kidney disease and have almost twice the risk of cardiovascular disease as people who do not carry this gene. The gene is present in 1 in 10 blacks and is uncommon in whites and non-African populations.  Scientists believe that this gene variant originated as a way to protect against sleeping sickness in Africa.

2. Even small spikes in blood pressure can lead to a higher risk of death.  A new analysis of data from the Jackson Heart Study found that for each 10 millimeters of mercury (mm Hg) increase in systolic blood pressure, there was a 12 percent higher risk of death for African-Americans and a 7 percent greater risk of hospitalization due to heart failure.  The finding could help improve future guidelines for treating hypertension in this at-risk population, the researchers say. The findings were published in December 2016 in the Journal of the American Heart Association

3.  Preventing heart disease is highly possible: While there’s no magic pill, researchers have found that there are concrete steps people can take to live a longer, more productive life—without heart disease.  In a study of more than 4,700 JHS participants, researchers found that those who adopted certain health measures had a lower risk for heart disease.  These measures, known as “Life’s Simple 7,” include managing blood pressure, controlling cholesterol, reducing blood sugar, getting more exercise, eating better, losing weight, and avoiding smoking.

In addition to these findings on heart disease, researchers have also made the following JHS discoveries, and more are anticipated:

4. Sickle cell trait is linked to a higher risk of kidney disease.  African-Americans with sickle cell trait have a nearly 60 percent higher risk of developing kidney disease than those without the trait. With sickle cell trait, people carry only one copy of the sickle cell gene variant instead of two and tend to have fewer medical complications compared to those with full-blown sickle cell disease.  Researchers suggest that people with sickle cell trait may need closer monitoring for signs of kidney disease. The study could lead to new ways to prevent kidney disease in this population, they say.

5. Target identified: Rare gene can lower the risk of diabetes.  Some gene defects can help protect you against disease. In 2014, researchers conducted a genetic analysis of 150,000 people and discovered that rare mutations in a gene called SLC30A8 lowered the risk of developing type 2 diabetes by 65 percent.  The gene was found in multiple ethnic groups, including a small number of participants from the Jackson Heart Study. The identification of this target could lead to a way to prevent diabetes, researchers suggest.