Prehypertension may increase risk of stroke

Even people with blood pressure that is slightly above normal may be at an increased risk of stroke, according to a review of studies published in the September 28, 2011, online issue of Neurology®, the medical journal of the American Academy of Neurology.

"With an estimated one out of three people in the United States having slightly elevated blood pressure levels, which is known as prehypertension, further studies are needed to look at whether reducing blood pressure in this group can help lower the risk of stroke," said study author Bruce Ovbiagele, MD, MSc, of the University of California, San Diego, and a Fellow of the American Academy of Neurology.

Prehypertension is defined by a systolic blood pressure (top number) of between 120 and 139 mmHg or diastolic blood pressure (bottom number) between 80 and 89 mmHg.

For the review, researchers analyzed the results of 12 previous studies involving the blood pressure and stroke occurrence of 518,520 adults. Studies were included by searching medical databases and libraries.

The review found people with prehypertension were 50 percent more likely to develop stroke compared to people with normal blood pressure levels, even after accounting for factors such as age, sex, diabetes, obesity, cholesterol and smoking.

In addition, young and middle age people may be at risk for stroke. The review found people under age 65 with prehypertension were nearly 80 percent more likely to develop a stroke compared to people with normal blood pressure. "These people may immediately benefit from blood pressure lowering methods, such as reducing their salt intake and weight, to help reduce their risk of stroke," Ovbiagele said.