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% 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.
Originally published in The Johns Hopkins White Papers: Memory (2011)
Written By: Peter V. Rabins, M.D., M.P.H. Director, Division of Geriatric Psychiatry and Neuropsychiatry Johns Hopkins University School of Medicine