Neurophysiologist Vera Novak of Beth Israel Deaconess Medical Center in Boston and colleagues reported that in older patients with diabetes, two adhesion molecules -- sVCAM and sICAM -- cause inflammation in the brain, triggering a series of events that affect blood vessels and eventually cause brain tissue to atrophy, which results in decreased cognition.
The study, published in the journal Diabetes Care, found the gray matter in the brain's frontal and temporal regions -- responsible for decision-making, language, verbal memory and complex tasks -- is the area most affected by these events.
The study involved 147 study subjects, average age 65. Seventy-one of the subjects had type 2 diabetes and had been taking medication to manage their conditions for at least five years. The other 76 were age and sex-matched non-diabetic controls.
The subjects underwent functional magnetic resonance imaging testing to show changes in blood flow. The diabetic patients not only had greater blood vessel constriction than the control subjects, they also had more atrophied brain tissue, particularly gray matter, the researchers said.