In two years, people with type 2 diabetes experienced negative changes in their ability to regulate blood flow in the brain, which was associated with lower scores on tests of cognition skills and their ability to perform their daily activities, according to a study.

OT_News-01Findings appeared in the July 8 online issue of Neurology, the journal of the American Academy of Neurology.

“Normal blood flow regulation allows the brain to redistribute blood to areas of the brain that have increased activity while performing certain tasks,” study author Vera Novak, MD, PhD, of Harvard Medical School, Boston, said in a news release. “People with type 2 diabetes have impaired blood flow regulation. Our results suggest that diabetes and high blood sugar impose a chronic negative effect on cognitive and decision-making skills.”

The study involved 40 people with an average age of 66. Of participants, 19 had type 2 diabetes and 21 did not have diabetes. Those with diabetes had been treated for the disease for an average of 13 years. The participants were tested at the beginning of the study and again two years later. Evaluations included cognition and memory tests, MRI scans of the brain to look at brain volume and blood flow, and blood tests to measure control of blood sugar and inflammation.

After two years, results showed the people with diabetes had decreases in their ability to regulate blood flow in the brain. Those with diabetes also had lower scores on several tests of memory and thinking skills, researchers found. People with lower ability to regulate blood flow at the beginning of the study had greater declines in a measure of how well they could complete daily activities such as bathing and cooking, the study showed.

Higher levels of inflammation also were associated with greater decreases in blood flow regulation, even if people had good control of their diabetes and blood pressure, Novak said in the release.

On a test of learning and memory, the scores of the people with diabetes decreased by 12%, from 46 points to 41 points in the two years of the study, while the scores of those without diabetes stayed the same, at 55 points. Blood flow regulation in the brain was decreased by 65% in people with diabetes.

“Early detection and monitoring of blood flow regulation may be an important predictor of accelerated changes in cognitive and decision-making skills,” Novak said in the release.

Additional studies involving more people and extending for a longer time period are needed to better understand the relationship and timing with blood flow regulation and changes in thinking and memory skills, she said in the release.

The study was supported by the National Institute on Aging, American Diabetes Association, Harvard Clinical and Translational Science Center and the National Center for Research Resources.

Study abstract: