"Silent" heart attack boosts dementia risk

NEW YORK (Reuters Health) - Men who are found to have had an unrecognized or “silent” heart attack are at increased risk of developing dementia or small lesions in the brain that can affect cognition, Dutch researchers report.

Dr. Monique M. B. Breteler told Reuters Health that her group had previously found that men, but not women, with a silent heart attack are more likely to have a stroke than men who had a recognized heart attack or those who had not had any heart attack.

To examine whether this might also be the case for dementia and so-called cerebral small vessel disease, Breteler of Erasmus University, Rotterdam, and her colleagues examined data for more than 6300 participants in a population-based study.

At the start of the study, from 1990 to 1993, the subjects were classified as having a recognized heart attack, not having a heart attack, or having had an unrecognized heart attack based on EKG tracings. They were followed for the occurrence of dementia, of which there were 613 cases by 2005.

The team also examined data for 436 subjects without dementia who underwent MRI brain scans.

Compared to men who had not had a heart attack, men with an unrecognized heart attack were more than twice as likely to develop dementia. They also had more brain lesions and showed signs of cerebral blood vessel blockages more often on MRI, the team reports in the American Heart Association’s journal Stroke.

There were no associations between dementia risk and unrecognized heart attacks in women, or among men and women with recognized heart attacks.

The researchers conclude that using an EKG to screen men to see if they’ve had an unrecognized heart attack “might identify those at an increased risk of various adverse outcomes.” They might then benefit from subsequent preventive therapy.

“However,” Breteler pointed out, “before such screening can be initiated, it should first be evaluated for efficacy and cost-effectiveness in adequately designed randomized controlled studies.”

SOURCE: Stroke, May 2008.