Most African-Americans develop high blood pressure by age 55, study finds

High blood pressure is often called "the silent killer" because it usually has no symptoms. Now new research shows most African-Americans will develop high blood pressure in middle age, putting them at greater risk of heart disease and other serious health problems.

Tracy Johnson was 46 when she was diagnosed. Five years ago, she was at work when she suddenly felt extremely warm.

"The nurse on the site checked my blood pressure and it was 220 over 120 and they sent me straight to the ER," Johnson told CBS News.

Johnson learned that she had hypertension, or high blood pressure, which runs in her family. New research in the Journal of the American Heart Association shows 75 percent of African-American men and women are likely to develop high blood pressure by age 55. That's compared to 55 percent of white men and 40 percent of white women.

"We started to see differences between blacks and whites by age 30," lead researcher S. Justin Thomas told HealthDay. Thomas, an assistant professor at the University of Alabama at Birmingham, said it's not clear why black Americans appear to be more at risk at younger ages than whites, but he speculated that a combination of lifestyle and genetic factors could come into play.

"Blood pressure is very complex," said Dr. Gautam Visveswaran, a cardiologist at Newark Beth Israel Medical Center. "A part of it relates to the genetic makeup, a part of it relates to diet, lifestyle."

Research confirms that following a diet designed to fight hypertension can lower a person's risk. Many doctors recommend the DASH diet, which stands for Dietary Approaches to Stop Hypertension. It emphasizes fresh fruits and vegetables, whole grains, healthy fats like olive oil, lean proteins, and low-fat dairy, while avoiding processed foods and those high in saturated fats. 

"Incorporate a healthy diet which is low salt and high in fruits and vegetables. Get to an exercise program. ... And go to your health care provider," said Visveswaran, who notes that high blood pressure is preventable.

Johnson has adopted some of these changes. "I don't eat fried foods anymore. I don't eat ice cream. I don't eat cheese," she said.

High blood pressure is a risk factor for heart disease, and three months ago, Johnson needed surgery for two blockages in her heart.

"When you're young you think you're invincible, so I wasn't worried about that then but I am now," she said.

Johnson says she is now more diligent about taking her medications, has lost some weight, and is exercising to stay healthy.