Elderly reduced cognition linked to type 2 diabetes

July 21, 2015

Harvard researchers discovered a link between T2DM and a chronic negative effect on cognitive and decision-making skills.

There is a need for new therapies focused on prevention of type 2 diabetes mellitus (T2DM)-related decline in the older population to focus on improving vascular control and reducing the impact of T2DM on the brain, according to a study published recently in Neurology

Vera Novak, MD, PhD, from Harvard Medical School in Boston, and colleagues, wanted to investigate how inflammation, blood flow regulation in the brain, and cognitive decline were related in people with the metabolic disorder.

Novak and her colleagues studied 65 participants (aged 66 ± 9.2 years), 35 with T2DM and 30 non-diabetic controls. After two years of follow-up, participants with T2DM had diminished vascular reactivity in the brain (an ability to increase blood flow in responses to a task or metabolic demands) and performed worse on multiple cognitive tasks (in particular verbal learning and memory). In the T2DM group, lower cerebral vasoreactivity correlated with worse performance on daily living activities. Specifically, the lower vasodilatation (ability to increase blood flow) was associated with worse mental functions. In addition, those with higher markers of inflammation had greater decline in vascular function in the brain.

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“Our pilot study has shown that insulin administered via spray into the nose may have potential benefits for learning and memory,” Novak tells Medical Economics in an e-mail. “We will test this approach in our new clinical trial. Maintaining optimal T2DM control in combination with exercise and active healthy lifestyle regimen is very important for T2DM adults.”

Impaired blood flow regulation in the brain may accelerate brain aging and functional decline, according to Novak, associate professor of neurology in Harvard Medical School's Department of Neurology (Stroke Division) and director of the Syncope and Falls in the Elderly (SAFE) Laboratory.

“Worse performance on daily activities, worse memory, or slower gait speed in older diabetic adults may thus hallmark a decline in ability to regulate blood flow in the brain,” she says.