Diabetes May Actually Slow Progression of Alzheimer's Disease, Not Increase It

October 29, 2009

In contrast to earlier research, new findings from the American Academy of Neurology show that diabetes may slow the progression of memory loss in Alzheimer's patients, not increase it.

Previous research has shown that diabetes may increase a person’s risk for developing Alzheimer’s disease and increase the chance for memory loss in patients who do not have Alzheimer’s disease. New research from the American Academy of Neurology shows, however, that people with both diseases actually have a slower rate of memory loss than those patients with Alzheimer’s disease but not diabetes.

When the study began, patients with and without diabetes scored an average of 20 points on a cognitive test. During each of the six-month testing periods, the overall score of the group on the cognitive test declined by 1.24 points. However, according to study author Caroline Sanz, MD, of INSERM, the French National Institute for Health and Medical Research, and her colleagues, patients without diabetes “declined by 0.38 points more per six-month period than those with diabetes.”

Despite the findings of the study, the researchers say they are not sure why people with diabetes experienced a slower rate of memory loss.

“One possible explanation is that diabetes in the elderly differs from that in younger people and in addition, elderly people with diabetes may be more likely to receive cardiovascular medications such as drugs for high blood pressure than people who don’t have diabetes,” Sanz said. “These drugs have been reported to decrease the risk of developing Alzheimer’s disease and also the rate of cognitive decline in people with Alzheimer’s disease. Other possible explanations for these findings may relate to differences in brain lesions in those people with diabetes compared to those without diabetes.”

The researchers followed 608 people with mild to moderate Alzheimer’s over the course of four years, testing their memory and thinking skills twice a year. Of the 608 participants, 63 had diabetes as well as mild or moderate Alzheimer’s, or 10.4%.

Results of the study were also published in Neurology.