Diabetes Treatment and Alzheimer Disease

People who take insulin and another diabetes drug may be at a lower risk of developing Alzheimer disease than those taking just one diabetes drug, according to a new study.


Previous studies have shown that people who have diabetes have a higher risk of getting Alzheimer disease than people who don’t. In fact, recent research into insulin resistance in the brain has prompted some experts to dub Alzheimer disease “Type 3 diabetes.”

The results of a new study about diabetes and Alzheimer disease were reported in late July at the International Conference on Alzheimer’s Disease. In this study, researchers examined the brains of 248 elderly people who had died—124 had diabetes and 124 did not. The two groups were matched by age, sex, and how severe their dementia was (on average, dementia was moderate to severe). Within the group of people who had diabetes, 29 were not taking any diabetes drugs, 49 were taking insulin only, 28 were taking diabetes drugs other than insulin (mostly sulfonylureas), and 18 were taking insulin and another diabetes drug.

The researchers found that the people taking insulin and another drug had significantly fewer beta-amyloid plaques on their brains than any of the other groups. Beta-amyloid plaques on the brain are a sign of Alzheimer disease, though what role they play in its progression is not yet well understood.

One researcher who worked on the study hypothesized that, in people who are treated with an oral diabetes drug as well as insulin, the insulin may be more effective and therefore lower their risk for Alzheimer disease. And Michal Beeri, Ph.D., who led the study at Mount Sinai School of Medicine in New York, commented that “the combination of insulin and oral anti-diabetes medications may beneficially influence Alzheimer-related brain changes.”

However, Beeri also pointed out that the study was unable to conclude whether the combination treatment actually caused the reduction in plaques observed in the brain. Nevertheless, she said that the study’s findings may help scientists develop new treatments for Alzheimer disease.

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  • suzanne

    It’s never been clear to me whether this increased risk for Alzheimer’s applies to people with type 1 diabetes. Is it just an issue for those with insulin resistance?? I have type 1 – do I need to worry about Alzheimer’s too?

  • rebecca

    This article does not really clarify whether or not people with Type I diabetes can get Alzheimer’s or not. It is just stating what findings have been made, but doesn’t tell us whether or not we should be tested to see if we can develop Alzheimer’s. I have Alzheimer’s running in my family and I fear I will get it eventually, also. What are we supposed to do to find out?

  • Tara Dairman, Web Editor

    Hi Suzanne and Rebecca,

    You raise some important questions.

    This article from the NY Times, though a couple of years old, gives a pretty good overview of the links that researchers have found between diabetes and Alzheimer disease. The research has focused heavily on Type 2 diabetes, since insulin resistance seems to be associated with Alzheimer risk.

    As for a Type 1-Alzheimer connection, I was able to find one animal study in which the brains of rats were examined for signs of Alzheimer disease after the rats had lived with either Type 1 or Type 2 diabetes for eight months. Changes were found in the brains of both groups of rats, but they were more severe in the Type 2 group. You can read the abstract of that study here.

    In any case, there is some evidence that steps you take to protect against other diabetes complications—controlling blood glucose levels, exercising, eating a healthy diet—can also help protect you against Alzheimer disease. Some studies have also shown benefit from eating a Mediterranean diet and omega-3 fatty acids; you can read more about them in “Studies Find Benefit for Fish and Omega-3 Consumption.”