Having blood pressure that’s even slightly above what doctors consider to be normal can increase your risk of a stroke, a new review has found.

The meta-review looked at several recent studies on the risk of stroke in people with “prehypertension.” That’s a blood pressure higher than the optimal 120/80 mmHg -- or “120 over 80” – and yet lower than the accepted threshold for high blood pressure: 140/90 mmHg.

The researchers looked at 19 studies involving more than 760,000 participants who were followed for anywhere from four to 36 years.

They found that people with pre-high blood pressure were 66 per cent more likely to (experience a stroke than people who had normal blood pressure.

The risk was still high even after researchers adjusted for other factors that could increase the likelihood of stroke, such as high cholesterol, diabetes and smoking.

As well, further investigation revealed that nearly one-fifth of the strokes in the study groups were directly due to pre-high blood pressure.

The study appears in the online issue of Neurology.

Study author Dr. Dingli Xu, of Southern Medical University in Guangzhou, China, says considering how many people have higher than normal blood pressure, bringing those pressure readings down with changes in diet and exercise could prevent many strokes “and make a major difference in public health.”

CTV medical specialist Dr. Marla Shapiro, who was not involved in the study, says the research shows there’s a risk to any form of elevated blood pressure.

“We’re beginning to see that blood pressure even in that range that we used to think of as acceptable carries a risk for stroke,” she told CTV News Channel.

Shapiro added that while not everyone in the pre-hypertension range needs to be treated with medications, they should examine which lifestyle factors they could change, such as reducing alcohol intake and stress.

“And your salt intake -- and we’ve talked a lot about salt a lot because Canadian take in way too much salt -- that sedentary lifestyle we lead -- all these lifestyle changes you can make to drive your blood pressure down and keep you in the right range,” Shapiro said.