High blood pressure has been called the silent killer, because it can creep up without warning, putting people at risk for heart disease, stroke, and a variety of other illnesses. Studies on older adults have shown that high blood pressure is also related to a decline in mental abilities. A new study from U.S. and Australian researchers now says that mental capacity could go down as blood pressure goes up not just among the elderly but among adults of all ages.

What the researchers wanted to know: Is high blood pressure related to decreased mental capacities?

What they did: The researchers used data from a larger study looking at blood pressure. They took people's blood pressure and gave them a test that measured different mental tasks, such as arithmetic, verbal skills, memory, and picture arrangement. Then, they followed up after about five years, again measuring blood pressure and administering the cognitive test. Most patients had only one follow-up visit, but some were tracked for nearly 20 years.

What they found: People who had high blood pressure as young adults were more likely to perform worse on certain parts of the mental test as they got older. Specifically, people with high blood pressure declined more than those with normal blood pressure in what the researchers called visualization/fluid abilities—completing a picture and arranging pictures and objects. The researchers say their results are consistent with other studies showing that high blood pressure is related to cognitive abilities, especially with tasks that measure a person's ability to deal with changing situations.

What it means to you: High blood pressure appears to be related to mild declines in mental functioning as people age. Mental decline and conditions such as Alzheimer's disease are difficult to prevent, but high blood pressure can often be lowered.

Caveats: The subjects in this study were relatively well educated and concerned about their mental abilities, which could have made them more conscious of keeping their minds agile throughout the study. If that is the case, the effects of this study might extend to other mental abilities in addition to those these researchers found.

Find out more: The National Institutes of Health has a Web page devoted to explaining blood pressure, high blood pressure, and how you can lower yours.

For more about the study cited in this article, known as the Maine-Syracuse Study

Read the article: Elias, P. K. "Blood Pressure-Related Cognitive Decline: Does Age Make a Difference?" Hypertension. Nov. 2004, Vol. 44, No. 5, pp. 631–636.

Abstract online: http://hyper.ahajournals.org