The analysis of data from seven studies involving more than 61,000 people is one of the most comprehensive studies ever conducted examining how changes in blood pressure during middle age affect lifetime risk of heart disease and stroke.
Researchers confirmed that people with normal blood pressure at age 55 had a relatively low lifetime risk for heart disease or stroke -- between 22% and 41%.
In contrast, those who had already developed high blood pressure by this age had a higher lifetime risk of between 42% and 69%.
The findings highlight the importance of maintaining normal blood pressure throughout middle age and even earlier, says researcher Norrina Allen, PhD, of Chicago’s Northwestern University Feinberg School of Medicine.
More than 74 million adults in the U.S. have high blood pressure, meaning that their systolic pressure (the top number) is 140 mmHg or higher and their diastolic pressure is 90 mmHg or above.
“People who maintained a low blood pressure of less than 120 over 80 had the lowest lifetime risk for [heart disease and stroke], and those who stayed above 140 over 90 had the highest,” Allen tells WebMD. “The longer people can delay the onset of hypertension, the better off they are.”
Middle-Age BP Predicts Heart, Stroke Risk
Using the data, the researchers were able to estimate lifetime risk for heart attack, stroke, and other heart-related events for white and African-American adults.
Starting with a first-time reading at an average age of 41, the researchers tracked blood pressure changes until age 55 and then continued to follow the study participants until the occurrence of a heart attack, stroke, or other medically similar event, or until death or age 95.
By their mid-50s, about one in four men and two in five women still had normal blood pressure, and about half of men and women had blood pressure that was above normal but not yet high enough to be considered high.
Women had greater increases in blood pressure during middle age than men did, and African-American men and African-American women had a higher lifetime risk for high blood pressure, heart attack, and stroke than white men and women.
Based on their analysis, the researchers predicted that:
- More than two out of three (70%) men who developed high blood pressure in middle age will have a heart attack, stroke, or other such event by age 85.
- Half of women who develop high blood pressure by their early 40s will develop heart disease or increase their stroke risk later in life.
The study will appear in the Jan. 3 issue of the American Heart Association (AHA) journal Circulation.
‘Never Too Late to Lower Heart Attack, Stroke Risk’
The researchers were not able to examine the impact of drug treatments to control high blood pressure on lifetime heart attack and stroke risk.
That’s because drugs were not widely used to treat high blood pressure when the first blood pressure measurements were taken, Allen says.
American Heart Association president-elect Donna Arnett, PhD, says it is clear from clinical trials that drug treatments that control high blood pressure lower the lifetime risk of heart attack, stroke, and death from other similar causes.
Arnett, who chairs the department of epidemiology at the University of Alabama at Birmingham, tells WebMD that it is never too late to lower heart attack and stroke risk with lifestyle changes and drug treatments.
“This research shows that normal blood pressure in middle age is a good indicator of [heart and blood vessel] health later in life,” she says. “Remaining physically active, maintaining a healthy body weight, eating right, and drug treatments can all help people achieve this goal.”