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Alzheimer’s Blocked by Diabetic Drugs Like Metformin


Diabetes can increase Alzheimer’s risk. Learn how drug treatments for diabetes bring that risk back down.

Patients on medication for type 2 diabetes may be keeping Alzheimer’s disease at bay.

USC Dornsife psychologists have found that those patients with untreated diabetes developed signs of Alzheimer’s disease 1.6 times faster than people who did not have diabetes.

The study was published in the journal Diabetes Care.

Alzheimer’s Ties to Diabetes Medication

Galega officinalis, a natural source of galegine

Antidiabetic medications, which also includes the withdrawn agents phenformin and buformin, originates from the French lilac or goat’s rue (Galega officinalis), a plant used in folk medicine for several centuries.

“Our findings emphasize the importance of catching diabetes or other metabolic diseases in adults as early as you can,” says Daniel A. Nation, associate professor of psychology at USC Dornsife College of Letters, Arts and Sciences. “Among people with diabetes, the difference in their rate of developing the signs of dementia and Alzheimer’s is clearly tied somehow to whether or not they are on medication for it.”

Nation says that this study may be the first to compare the rate of developing the pathology for Alzheimer’s disease and dementia among people with normal glucose levels, with prediabetes, or people with type 2 diabetes — both treated and untreated.

Biomarkers for Diabetes

For the study, the scientists were comparing the “tau pathology” — the progression of the brain tangles that are the hallmark of Alzheimer’s disease. When the tangles combine with sticky beta-amyloid plaques — a toxic protein — they disrupt signals between brain cells, impairing memory and other functions.

Nation and Elissa McIntosh, a USC Dornsife Ph.D. doctoral candidate in psychology, analyzed data collected by the Alzheimer’s Disease Neuroimaging Initiative (ADNI) on nearly 1,300 people age 55 and older. Data included biomarkers for diabetes and vascular disease, brain scans and a range of health indicators, including performance on memory tests.

Lots of Data

For some participants, Nation and McIntosh were able to analyze 10 years’ worth of data, while for others, they had one or four years.

Among 900 of those patients, a little more than 50 had type 2 diabetes but were not being treated, while nearly 70 were receiving treatment. Most people in the study — 530 — had normal blood sugar levels while 250 had prediabetes (hyperglycemia).

Need to Investigate How It Works

Actos Significantly Decreases Alzheimer’s Risk

Diabetics get a lot more dementia than the average person. Yet diabetics taking FDA-approved Actos get a lot LESS dementia than the average person – 47% less. That’s about half the rate. Find out more.

Increasingly, scientists regard Alzheimer’s disease as the result of a cascade of multiple problems instead of just one or two. The compounding factors range from pollution exposure and genetics (the ApoE4 gene, for instance) to heart disease and metabolic disease.

The researchers compared, among the different diabetic patient categories, the brain and spinal fluid test results that can indicate signs of amyloid plaques and the brain tangles.

“It is possible that the medicines for treating diabetes might make a difference in the progression of brain degeneration,” Nation says. “But it’s unclear how exactly those medications might slow or prevent the onset of Alzheimer’s disease, so that is something we need to investigate,” Nation says.


  • Elissa C. McIntosh, Daniel A. Nation, for the Alzheimer’s Disease Neuroimaging Initiative for the Alzheimer’s Disease Neuroimaging Initiative. Importance of Treatment Status in Links Between Type 2 Diabetes and Alzheimer Disease. Diabetes Care, 2019 DOI: 10.2337/dc18-1399


  • The study was supported by National Institutes of Health grants R21-AG-055034, P01-AG-052350 and P50-AG-005142 and Alzheimer’s Association grant AA-008369.
  • The Alzheimer’s Disease Neuroimaging Initiative (ADNI) is supported by the National Institute on Aging and the National Institute of Biomedical Imaging and Bioengineering, as well as other public and private partners.


  • University of Southern California – Dornsife
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June 11, 2019 2:41 am

Not sure how it works??? I am not a physician, but here is my oh-so-humble opinion. Scroll down to blood sugar in this blog post:

There you will find the relationship of high blood sugar to Alzheimer's risk, shown in study after study. Metformin lowers blood sugar. OK, I'll get off my soap box now.

October 18, 2020 6:06 am

Sent you a reply on your blog Otto.

B. Berger

B. Berger

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