Cerebral microbleeds more common than previously thought

New research shows cerebral microbleeds, which are lesions in the brain, are more common in people over 60 than previously thought.

The study is published in the April 1, 2008, issue of Neurology, the medical journal of the American Academy of Neurology.

“We found a three-to-four-fold higher overall prevalence of cerebral microbleeds compared to other studies,” according to study author Monique M.B. Breteler, MD, PhD, with the Erasmus MC University Medical Center in Rotterdam, the Netherlands. “These findings are of major importance since cerebral microbleeds likely reflect cerebrovascular pathology and may be associated with an increased risk of cerebrovascular problems.”

Cerebral microbleeds are lesions that can be seen on brain scans, such as an MRI brain scan. The lesions are deposits of iron from red blood cells that have presumably leaked out of small brain vessels.

For the study, 1,062 healthy men and women who were an average age of 70 underwent an MRI to scan for the presence of cerebral microbleeds. Of the participants, 250 were found to have cerebral microbleeds.

The study found overall prevalence of cerebral microbleeds was high and increased with age from 18 percent in people age 60 to 69 to 38 percent in people over age 80. People with the e4 allele of the APOE gene, which is known to increase the risk of Alzheimer's disease and of cerebral amyloid angiopathy, had significantly more microbleeds than people without this genetic variant.

“We also found that the risk factors for cerebral microbleeds appear to vary according to the location of the microbleed,” said Breteler. “Our results show people with high blood pressure and a history of smoking had microbleeds in a different location in the brain than people with the APOE e4 allele, suggesting different causes for microbleeds in different locations.”