THURSDAY, Nov. 1 (HealthDay News) -- High blood pressure can damage the structure of the brain in people as young as 40, a new study finds.

Structural damage was found even in the brains of young middle-aged people who had pre-hypertension, in which blood pressure is elevated but not to the level considered to be high blood pressure.

Researchers looked at nearly 600 people who were an average of 39 years old when the study was launched in 2009. Their blood pressure was checked and they underwent MRI brain scans.

Accelerated brain aging was found in people with hypertension as well as those with pre-hypertension, including damage to the structural integrity of white matter and the volume of grey matter.

The study is the first to find that elevated blood pressure damages the brains of young middle-aged adults and suggests that blood-pressure-related brain damage occurs over a lifetime, the researchers said.

Previous research has linked blood-pressure-related damage to the brain's white matter with mental decline in older people, the study authors noted.

"The message here is really clear: People can influence their late-life brain health by knowing and treating their blood pressure at a young age, when you wouldn't necessarily be thinking about it," study senior author Charles DeCarli, professor of neurology and director of the Alzheimer's Disease Center at the University of California, Davis, said in a university news release.

The study was published online Oct. 31 in The Lancet Neurology, and appears in the December print issue of the journal.

Elevated blood pressure, which affects about 50 million Americans, is associated with an increased risk of stroke and cardiovascular disease and is the single greatest risk factor for death in the United States.

More information

The U.S. National Heart, Lung, and Blood Institute has more about high blood pressure.