New predictor of heart attack

A hike in your blood pressure during middle age significantly raises the risk of having a heart attack or a stroke during your lifetime, according to new Northwestern Medicine research. The study offers a new understanding on the importance of maintaining low blood pressure early in middle age to prevent heart disease later in life.

Men and women who developed high blood pressure in middle age or who started out with high blood pressure had an estimated 30% increased risk of having a heart attack or stroke compared to those who kept their blood pressure low.

Previous estimates of a person's risk of cardiovascular disease were based on a single blood pressure measurement. The higher the blood pressure reading, the greater the risk. The new Northwestern Medicine study expands on that by showing a more accurate predictor is a change in blood pressure from age 41 to 55.

The study is published in Circulation: Journal of the American Heart Association.

"We found the longer we can prevent hypertension or postpone it, the lower the risk for cardiovascular disease," said lead author Norrina Allen, assistant professor of preventive medicine at Northwestern University Feinberg School of Medicine. "Even for people with normal blood pressure, we want to make sure they keep it at that level, and it doesn't start increasing over time."

"There hasn't been as much of a focus on keeping it low when people are in their 40's and 50's," Allen added. "That's before a lot of people start focusing on cardiovascular disease risk factors. We've shown it's vital to start early."

The study

People that maintain or reduce their blood pressure to normal levels by age 55 have the lowest lifetime risk for a heart attack or a stroke.

The study used data from 61,585 participants in the Cardiovascular Lifetime Risk Pooling Project. Starting with baseline blood pressure readings at age 41, researchers measured blood pressure again at age 55, then followed the patients until the occurrence of a first heart attack or stroke, death or age 95.

Men who developed high blood pressure in middle age or who started out with high blood pressure had a 70% risk of having a heart attack or stroke compared to a 41% risk for men who maintained low blood pressure or whose blood pressure decreased during the time period. Women who developed high blood pressure had almost a 50% risk of a heart attack or stroke compared to a 22% risk for those who kept their blood pressure low or saw a decrease.

Men generally have a 55% risk of cardiovascular disease in their lifetimes; women have a 40% risk.

"Our research suggests people can take preventive steps to keep their blood pressure low early on to reduce their chances of a heart attack or stroke," said Donald M. Lloyd-Jones, MD, study co-author, chair of preventive medicine at Northwestern's Feinberg School and a cardiologist at Northwestern Memorial Hospital. "Maintaining a healthy diet, combined with exercise and weight control, can help reduce blood pressure levels and, consequently, your risk for cardiovascular disease later in life."

(EurekAlert, December 2011)