Study Shows Diabetes Increases Dementia Risks

If you have diabetes, you could be at increased risk for dementia, including Alzheimer’s disease and vascular dementia.  But researchers are not in agreement about why this is the case or what can be done to reduce the risks.

Diabetes results when excess sugar or glucose accumulates in the blood. Over time, this excess sugar can cause damage to small blood vessels, including blood vessels in the brain.  This can lead to blocked blood vessels and reduced blood flow which limits the supply of oxygen to the brain.  Vascular dementia is a condition resulting from damage to the brain caused by limited blood flow, such as when blood vessels in the brain are damaged.  Vascular dementia can cause problems with memory, judgment, reasoning, planning, and other thought processes.

In a recent study published in Neurology ®, the medical journal of the American Academy of Neurology, scientists in Japan found that people age 60 or older with diabetes were twice as likely to develop dementia as people without diabetes, based on a comparison of normal vs. elevated blood sugar levels.  The study also showed that having elevated blood sugar levels two hours after eating was a significant risk factor for developing dementia.  People who did not have diabetes but had “pre-diabetes” or impaired glucose tolerance were also at higher risk.  The Japanese researchers suggested this study gives people with diabetes another significant reason to control their sugar levels.

Another study published in The Lancet Neurology also recognized the connection between diabetes and dementia risks.   Researchers from the Laboratory of Epidemiology, Demography and Biometry at the U.S. National Institute on Aging indicated that older people with type 2 diabetes are at higher risks of mental impairment as well as brain atrophy than people without diabetes. The research team investigated whether intensive treatment to control blood glucose levels was more beneficial for brain function than standard blood sugar control.

Intensive blood glucose control is believed to reduce the risk of some other diabetic complications including damage to the kidneys, eyes, and blood vessels.  The research team expected the intensive treatment to have similar benefits for the brain.  However, after following patients through 40 months of treatment, they concluded that patients undergoing intensive glucose control and patients on standard treatment showed no difference on the cognitive function test used in the study.  The researchers concluded that the study did not support intensive blood glucose control as a way to reduce the risk of dementia in patients with diabetes.

Although participants in this study did not show reduced risk based on intensive blood glucose control, the research team says more studies are necessary before the possible benefits could be ruled out.   Current medical knowledge recommends managing diabetes to control blood sugar levels as the best strategy to avoid complications from the disease.   For people with pre-diabetes, diet and exercise to control weight can help prevent the development of type 2 diabetes and significantly reduce the risk of complications.

Denise DeWitt is a freelance writer for



Science Daily. Diabetes May Significantly Increase the Risk of Dementia. Web. February 26, 2012.

ABC News. Diabetes Puts People at Risk for Dementia, Study Finds. Carrie Gain. Web. February 26, 2012.

Fisher Center for Alzheimer’s Research Foundation. Diabetes Increases Dementia Risks, But Treatments are Limited. Web. February 26, 2012.

Mayo Clinic. Vascular dementia. Web. February 26, 2012.

Mayo Clinic. Diabetes and Alzheimer’s linked. Web. February 26, 2012.

Medical News Today. No Slowign of Cognitive Decline With Intensive Blood Sugar Control In Type 2 Diabetes. Web. February 26, 2012.

American Diabetes Assocation. Living With Diabetes: Stroke. Web. February 26, 2012.

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