Type 2 Diabetes Linked to Decreased Brain Blood Flow and Cognitive Ability

Vera Novak, MD PhD Associate Professor of Neurology Dept. of Neurology, Stroke Division Director Syncope and Falls in the Elderly Laboratory Beth Israel Deaconess Medical Center Boston, MAMedicalResearch.com Interview with:
Vera Novak, MD PhD
Associate Professor of Neurology
Dept. of Neurology, Stroke Division
Director Syncope and Falls in the Elderly Laboratory
Beth Israel Deaconess Medical Center
Boston, MA

MedicalResearch: What is the background for this study?

Dr. Novak: Diabetes mellitus (DM) is a major contributor to morbidity and mortality.
Type 2 diabetes mellitus affects more than 44 million people in the U.S., and its numbers are growing rapidly, affecting up to 27% of older adults. Diabetes mellitus accelerates brain aging by about 5 years1, manifests as a widespread generalized atrophy2, and promotes earlier onset of vascular dementia and Alzheimer’s disease (AD).3,4 Diabetes mellitus -related atrophy manifests as worse cognitive function, memory, and gait, especially during a dual task, 5,6 and even a tight glycemic control did not improve cognitive function in participants of the large clinical trials 7.

MedicalResearch: What are the main findings?

Dr. Novak: Sixty-five participants (aged 66± 9.2 years) 35 with T2DM and 30 non-diabetic controls participated in this study. After 2 years of follow-up, participants with T2 Diabetes mellitus 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 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.

MedicalResearch: What should clinicians and patients take away from your report?

Dr. Novak: Impaired blood flow regulation in the brain may accelerate brain aging and functional decline. Worse performance on daily activities, worse memory or slower gait speed 8 in older diabetic adults may thus hallmark a decline in ability to regulate blood flow in the brain.

MedicalResearch: What recommendations do you have for future research as a result of this study?

Dr. Novak: There is a need for new therapies focused on prevention of T2 Diabetes mellitus related decline in older population that would be focused on improving vascular control and reducing the impact of T2DM on the brain. Our pilot study has shown that insulin administered sprayed into the nose may have potential benefits for learning and memory 9, 10. 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.

Reference List

  1.         Franke,K., Gaser,C., Manor,B., & Novak,V. Advanced BrainAGE in older adults with type 2 diabetes mellitus. Front Aging Neurosci. 5, 90 (2013).
  2.         Cui,X., Abduljalil,A., Manor,B., Peng,C.K., & Novak,V. Multi-Scale glycemic variability: A link to gray matter atrophy and cognitive decline in type 2 diabetes. PLoS. One. 9, E86284E (2014).
  3.         Xu,W.L., Qiu,C.X., Wahlin,A., Winblad,B., & Fratiglioni,L. Diabetes mellitus and risk of dementia in the Kungsholmen project: a 6-year follow-up study. Neurology 63, 1181-1186 (2004).
  4.         Korf,E.S., White,L.R., Scheltens,P., & Launer,L.J. Brain aging in very old men with type 2 diabetes: the Honolulu-Asia Aging Study. Diabetes Care 29, 2268-2274 (2006).
  5.         Last,D. et al. Global and regional effects of type 2 diabetes mellitus on brain tissue volumes and cerebral vasoreactivity . Diabetes Care 30, 1193-1199 (2007).
  6.         Novak,V. et al. Adhesion molecules, altered vasoreactivity, and brain atrophy in type 2 diabetes. Diabetes Care 34, 2438-2441 (2011).
  7.         Launer,L.J. et al. Effects of intensive glucose lowering on brain structure and function in people with type 2 diabetes (ACCORD MIND): a randomised open-label substudy. Lancet Neurol. 10, 969-977 (2011).
  8.         Jor’dan,A., Manor,B., & Novak ,V. Slow gait speed-an indicator of lower cerebral vasoreactivity in type 2 diabetes mellitus. Frontiers in Aging Neuroscience Frontiers in Aging Neuroscience 6,135 (2014).
  9.         Novak,V. et al. Enhancement of Vasoreactivity and Cognition by Intranasal Insulin in Type 2 Diabetes. Diabetes Care 3, 751-759 (2014).
  10.         Zhang,H. et al. Intranasal insulin enhanced resting-state functional connectivity of hippocampal regions in type 2 diabetes. Diabetes 64:687-688 (2015).


Chen-Chih Chung, Daniela Pimentel, Azizah J. Jor’dan, Ying Hao, William Milberg, and Vera Novak. Inflammation-associated declines in cerebral vasoreactivity and cognition in type 2 diabetes. Neurology, July 2015 DOI: 10.1212/WNL.0000000000001820


Vera Novak, MD PhD (2015). Type 2 Diabetes Linked to Decreased Brain Blood Flow and Cognitive Ability 

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