The American Heart Association defines prehypertension as a systolic (top) blood pressure measurement of 120 to 139 mmHg or a diastolic (bottom) number of 80 to 89 mmHg, or both.
Researchers reporting in today's issue of Annals of Internal Medicine say that people who develop prehypertension before age 35 have an increased risk for subsequent calcium buildup in their coronary arteries. Coronary calcium is a sign of atherosclerosis, and is considered a predictor of future heart attacks and strokes.
"Our findings suggest the possibility that prehypertension itself is harmful, and not just because it is associated with subsequent [high blood pressure]," researcher Mark J. Pletcher, MD, MPH, says in a news release. "People with a lot of calcium in their coronary arteries are more likely to have heart attacks and strokes, and these outcomes might be avoidable by keeping blood pressure low when you're young."
High blood pressure in middle age is a leading risk factor for cardiovascular disease. But until now researchers did not know how mild increases in blood pressure influenced a younger adult's risk for such events.
Prehypertension Common in Young Adults
Pletcher and colleagues from the University of California, San Francisco analyzed 15 to 20 years worth of blood pressure readings from 3,560 adults aged 18 to 30. The blood pressure measurements were taken on seven different occasions, and near the end of the follow-up period, participants underwent a CT scan to look for coronary artery calcium.
Nearly one in five people developed prehypertension before age 35, and prehypertension was strongly associated with coronary calcification later in life. The amount of coronary artery calcium buildup increased the longer a young adult had prehypertension, and the higher their blood pressure readings. The top blood pressure measurement appeared to be more important than the bottom number.
"Prehypertension during young adulthood is common and is associated with coronary atherosclerosis 20 years later," the researchers write in the journal article.
The increased blood pressure measurements were most common among those who were African-American, male, overweight, and of low socioeconomic status. People without a college education who made less than $25,000 a year were twice as likely to develop prehypertension as were post-college graduates who made over six figures.
Everyone should strive for a healthy blood pressure. Blood pressure varies with activity, but normal blood pressure for adults at rest is less than 120/80 mmHg, according to the American Heart Association. Watching your weight, eating a healthy, balanced diet, and getting regular exercise can help keep your blood pressure in check and prevent hypertension.
"Keeping systolic pressure below 120 mmHg before age 35 years may provide important health benefits later in life," the researchers concluded.