How high is too high when it comes to blood pressure? New research suggests a reading a few points below the official benchmark for high blood pressure significantly increases the risk of heart attacks and strokes.
``The lower your blood pressure, the better off you are,'' said one of the researchers, Dr. Ramachandran S. Vasan of Boston University School of Medicine. ``Our finding emphasize the need for people to maintain optimal levels of blood pressure.''
The study of 6,859 men and women in Thursday's New England Journal of Medicine concluded that those with so-called high-normal blood pressure are two to three times more likely to suffer a heart attack, stroke or heart failure in 10 years than those with what is considered optimal or ideal blood pressure.
About 19 percent of adults in the United States have hypertension, or high blood pressure, and 13 percent have high-normal blood pressure, Vasan said.
``Individuals with high-normal blood pressure are a large chunk of the population and physicians need to share this information with them _ that there is now data to suggest they could be at increased risk,'' he said.
Blood pressure is the force of blood in the arteries and is measured in two numbers. The high number, systolic, is the pressure when the heart contracts. The lower number, diastolic, is the pressure between beats when the heart relaxes.
High blood pressure is above 140 over 90; high-normal is 130-139 over 85-89; normal is 120-129 over 80-84 and optimal is less than 120 over 80.
Those with high-normal blood pressure are often older, overweight, have high cholesterol or diabetes _ all possible contributors to heart disease, Vasan said.
Current guidelines suggest diet and exercise to lower high-normal blood pressure. Vasan said research is needed to determine whether more aggressive treatment, including medications, is warranted.
If studies show treatment is beneficial, the threshold for treating blood pressure with medications could be lowered, said Dr. Julio A. Panza of Washington Hospital Center, who wrote an accompanying editorial
``Depending on what other studies in the future show, it may have a significant implication,'' Panza said.
The study funded by the National Heart, Lung and Blood Institute reviewed data from the Framingham Heart Study, which has followed participants from the Boston suburb for more than half a century.
Vasan and his colleagues looked at groups of patients, and excluded those with high blood pressure or heart disease. They followed the rest for 12 years to find the rate of heart attack, stroke or heart failure.
Of those with high-normal blood pressure, 4 percent of the women and 8 percent of the men under 65 had an incident. In older participants, 65 to 90, the rate was 18 percent for women and 25 percent for men.
The researchers calculated that the women were about three times more likely and the men were about two times more likely to have a cardiovascular event than those with optimal blood pressure.