African-Americans have higher risk of high blood pressure earlier

By Dr. Ananya Mandal, MDSep 13 2011

According to a study published Monday, African-Americans who have slightly elevated blood pressure and don't do anything to change their lifestyle are more likely to have high blood pressure one year earlier than whites with similar pre-hypertension

Blood pressure numbers between 120-139 systolic (upper number) or 80-89 diastolic (lower number) are considered prehypertension.  High blood pressure is defined as 140/90 mm Hg and greater.

Previous studies have shown that blacks have higher rates of high blood pressure, heart disease and stroke compared to whites.  This new study says African-Americans with prehypertension are more likely to progress to having high blood pressure compared to whites in the same situation, suggesting the need for earlier interventions among black patients to potentially eliminate the disparities between races for hypertension.

Scientists from the Medical University of South Carolina examined electronic health records from clinics in the southeastern U.S. for 18,865 people aged 18 to 85 years between 2003 and 2009. None of the participants had high blood pressure at the study onset. 30.4% of the participants were African-American and 69.6% were white.

The researchers examined each participant’s risk factors for hypertension, including age, sex, weight, initial blood pressure, and whether subjects had type 2 diabetes or kidney disease. 63.8% of patients progressed to hypertension. And those patients were more likely to be obese (43%) diabetic (27.4%) and older than the others. African-American participants who developed prehypertension had a 35% greater risk for progression to high blood pressure than white participants.

While the study, published in the journal Hypertension, does not explain why blacks have higher rates of movement from prehypertension to hypertension, a related editorial by Edward D. Frohlich of the Ochsner Clinic Foundation in New Orleans, Louisiana, suggests that one explanation for the difference “may be based on the greater dietary intake of salt during one’s lifetime, especially in black individuals who are genetically predisposed to these severe target organ complications of hypertension.”

Limiting salt intake, losing weight and maintaining a healthy weight, having regular physical activity, managing cholesterol levels, eating a healthy diet high in fruits and vegetables, and limiting fat intake can all help to keep blood pressure rates in the healthy zone.

The risk factors include increasing age, ethnicity (African-Caribbean and South-Asian communities are more at risk), genetic or family history, lifestyle flaws including high intake of alcohol, excessive smoking, too much salt and not eating sufficient fruits and vegetables, lack of exercise etc.