Lowering Blood Glucose Levels May Improve Memory in Older Adults With Diabetes

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Improving metabolic control leads to better working memory in adults with type 2 diabetes, by C.M. Ryan and colleagues. Diabetes Care 29:345–351, 2006.

What is the problem and what is known about it so far?

Older adults with type 2 diabetes have a higher risk of having memory problems and difficulties with understanding things. However, it is not known whether this higher risk has something to do with always having high blood glucose levels or always having high insulin levels. If either high blood glucose or high insulin causes these thinking and memory problems, then it would seem that improving control over blood glucose and insulin levels would solve the problem. However, there are few studies that support that idea or have even included insulin levels in their tests.

Why did the researchers do this particular study?

The researchers wanted to find out if improving blood glucose levels can help prevent thinking and memory problems. One other major goal of the study was to find out if insulin resistance, or having high insulin levels, can affect how the mind works.

Who was studied?

A total of 145 people who were on metformin, which is a medication that helps control glucose levels. On average, the patients were around 60 years old.

How was the study done?

In addition to their metformin, the patients were given either rosiglitazone (which improves insulin sensitivity) or glyburide (which promotes insulin production). The subjects had check-ups over a six-month period and completed a series of learning and memory tests at the beginning and end of the study.

What did the researchers find?

The research team found that both rosiglitazone and glyburide improved blood glucose levels. Likewise, the patients scored much better on the thinking and memory tests after starting rosiglitazone or glyburide in addition to their metformin.

What were the limitations of the study?

The test scores of the people in this study were not compared with test scores of people who don't have diabetes.

Also, the people in this study had pretty good blood glucose control at the beginning of the study, and they didn't have thinking or memory problems to begin with. The results could be different for those who already have poor glucose control and/or thinking and memory problems.

What are the implications of the study?

The strong link between lower blood glucose and better memory scores indicates that efforts to lower blood glucose levels may improve memory in many older adults with diabetes.

FOR MORE INFORMATION

Low Blood Glucose Affects Memory in Children With Type 1 Diabetes

Diabetes and function in different cognitive systems in older individuals without dementia, by Z. Arvanitakis and colleagues. Diabetes Care 29:560–565, 2006.

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