Higher HbA1c = Lower Brain Function?

Following on the heels of last week’s blog entry ("Diabetes, Exercise, Outlook, and Your Brain"), which summarized some recent research about things that may affect brain function, comes another study looking at the effects of high blood glucose on the brain. Published online this week in the journal Diabetes Care, the new study has found a link between higher HbA1c levels and lower cognitive functioning in people with Type 2 diabetes.

The new study, called Memory in Diabetes (MIND), is actually a substudy of the ACCORD trial, a large study of tight blood glucose control and cardiovascular disease risk in people with Type 2 diabetes. In this substudy, almost 3,000 trial participants, with an average age of 62.5 and an average HbA1c of 8.3%, took four tests of cognitive function (the ability to think, reason, and remember). After adjusting for factors such as age and education, the researchers found that people with higher HbA1c levels scored lower on three of the tests than those with lower HbA1c levels. Higher HbA1c levels were associated with poorer speed, memory, and ability to learn and pay attention during the tests.

Advertisement

You can read the full study here.

MIND is an ongoing study, in which participants will be tested in these areas three times over the course of the trial, which ends later this year. One of the trial’s aims is to see whether lowering HbA1c level can improve a person’s cognitive function. However, the researchers do not know whether the cognitive impairment they observed is caused by higher blood glucose levels, or whether people who already have cognitive impairment are less able to control their blood glucose levels.

What do you predict the researchers will find? Do you feel like you think better when your blood glucose levels are within your target range? Leave a comment with your thoughts.

  • CalgaryDiabetic

    Dear Tara.

    You write correctly:” However, the researchers do not know whether the cognitive impairment they observed is caused by higher blood glucose levels, or whether people who already have cognitive impairment are less able to control their blood glucose levels.”

    This is the classic impossibility of determining what is the cause and what is the effect in a closed loop feedback system.

    Since controlling your BG is a very difficult mental task. It is reasonable to assume that someone impaired would not do as well.

    Also it is possible that high BG impairs the brain function.

    Possibly a cognitive measuremnt should be done on the same humans on a day their blood sugar is in the normal range vs a day it is high. Repeat this with many humans and see if high BG is like alcohol.

  • obviscator

    When I was diagnosed 6 months ago my A1c was over 300 and i was having LOTs of trouble in school. I have learned to control my glucose level and have seen a marked improvment in my ability to concentrate and comprehend.

  • Virginia

    I have had diabetes 2 since October 2005 and my HbA1C has averaged 5.6% during all this time. I have experienced a loss of concentration and
    challenges with memory recall. While I cannot say for certain this is due to diabetes, it was not as pronounced before being diagnosed with Diabetes 2.