Research: High Blood Sugar and Diabetes Have a Negative Effect on Cognitive Skills

16 Jul 2015 --- Participants with type two diabetes in a two-year study experienced negative changes in their ability to regulate blood flow to the brain, which was then linked to lower scores on cognition skills tests and their capacity to perform daily activities. The study, published in the Neurology journal, highlights the importance of blood sugar control in maintaining cognitive function in those with type 2 diabetes.

“Normal blood flow regulation allows the brain to redistribute blood to areas of the brain that have increased activity while performing certain tasks,” said Vera Novak from the Harvard Medical School in Boston, and the study’s lead author.

“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 included 40 people who were 66 years old on average, of which, 19 suffered from type 2 diabetes and 21 did not. Those suffering from diabetes had received some sort of treatment for 13 years on average. The enrollees, who were initially assessed when the study was initiated as well as two years after, were evaluated using memory and cognition tests, brain MRI scans to assess blood flow and brain volume, and blood tests to evaluate the control of blood sugar and the inflammation process.

Within the two years that patients were followed, those who had diabetes were observed to experience a decrease in their capacity to regulate blood flow in the brain. The results showed lower scores on several different memory and cognitive skills tests. People with less capacity to regulate blood flow at the start of the study had an increased decline in the ability to complete daily activities like cooking or bathing.

More inflammation was also linked to a greater decrease in blood flow regulation, even if individuals reported better control of their blood pressure and diabetes, noted Novak.

In a test involving learning and memory, the scores of the people with diabetes decreased by 12 percent, from 46 points to 41 points over 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 percent 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 concluded.