Information about Dementia Risk and High Blood Sugar

Research points to a link between diabetes and the risk of cognitive decline and Alzheimer's disease. A report from the Archives of Neurology found that among 824 people older than age 55, those with diabetes had lower scores on many measures of cognition and a 65 percent greater risk of developing Alzheimer's up to nine years later than those who didn't have diabetes.

In a study published in Neurology, older women with impaired glucose tolerance (prediabetes) scored worse on a series of cognitive tests than women with normal glucose tolerance—and women with diabetes scored the worst of all.

Moreover, retesting four years later showed that the women with diabetes had experienced the greatest decline in cognitive function. Overall, the risk of developing cognitive impairment was nearly twofold higher in women with either prediabetes or diabetes.

Researchers have several theories for how diabetes contributes to cognitive decline: The disease may injure tiny blood vessels in the brain (as it does blood vessels throughout the body); excess blood glucose (sugar) may be toxic to brain cells; or high levels of circulating insulin may interfere with the natural breakdown of the Alzheimer's-associated protein beta-amyloid.

Researchers at the University of Washington have discovered that people with high blood sugar levels may have an increased risk of developing dementia than those with normal levels. The study, published in the New England Journal of Medicine, revealed that among participants with diabetes, the risk of dementia was 40 percent higher for those with an average glucose level of 190 mg/dL when compared with participants who had an average glucose level of 160 mg/dL.

Originally published in The Johns Hopkins White Papers: Memory (2011); Updated by Remedy Health Media

Publication Review By: Peter V. Rabins, M.D., M.P.H.

Published: 07 Mar 2011

Last Modified: 11 Sep 2015