The study is one of the first to examine prospectively the relationship between blood pressure and secondary risk exclusively in women, according to lead author Peter J. Mason, M.D., M.P.H.
"We found a strong continuous relationship between increasing blood pressure and the risk of secondary cardiovascular (CVD) events in women, and that even borderline elevations in blood pressure are associated with an increased risk," Mason said.
Mason did the research as a National Heart, Lung, and Blood Institute-sponsored cardiovascular epidemiology fellow at the Brigham and Women's Hospital Division of Preventive Medicine. He is currently a cardiology fellow at Boston Medical Center.
The prospective study of 5,218 female health professionals (average age 62) found that for each 10 millimeters of mercury (mm Hg) increase in systolic blood pressure (the top number in a reading), a woman's CVD risk increased 9 percent.
High blood pressure causes the heart to work harder than normal to pump blood, causing it to enlarge and weaken over time. Most of the earlier studies that have examined the association between blood pressure and CVD risk focused on patients without known heart or blood vessel disease.
The women in this study -- followed an average of 6 years -- are part of the larger Women's Antioxidant Cardiovascular Study. The WACS is an ongoing double-blind, placebo-controlled secondary prevention trial of the benefits and risks of antioxidant vitamins, folic acid and vitamins B6 and B12 among women with CVD or three or more coronary risk factors. Women in the current study had confirmed CVD events such as heart attack or stroke, coronary artery bypass graft or angioplasty.