Washington, June 7 (IANS): Having a stroke ages a person's brain function by almost eight years, robbing them of memory and thinking speed, new research says.

In both black and white patients, the researchers found that having had a stroke meant that their score on a 27-item test of memory and thinking speed had dropped as much as it would have if they had aged 7.9 years overnight.

"The results show the amount of cognitive aging that stroke brings on, and, therefore, the importance of stroke prevention to reduce the risk of cognitive decline," said lead study author and assistant professor Deborah Levine from the University of Michigan.

For the study, data from more than 4,900 black and white participants - over the age of 65 was analysed.

By measuring participants' changes in cognitive test scores over time from 1998 to 2012, the researchers could see that both blacks and whites did significantly worse on the test after their stroke than they had before.

The researchers say the findings underscore the importance of stroke prevention.

Levine and her colleagues said that certain factors - such as how many years a person has vascular risk factors, and the quality of his or her education, as well as genetic and biological factors - might play a role in racial differences in long-term cognitive performance.

But one thing is clear: strokes have serious consequences for brain function.

Controlling blood pressure and cholesterol, avoiding smoking, controlling blood sugar in diabetes and being active even in older age can safeguard you against stroke.

The results are forthcoming in the journal Stroke.