Elevated BG and Dementia: What’s the Risk?



Put the words “diabetes” and “dementia” together and you’re sure to get a lot of attention, but sometimes you have to look past the headlines.

Two new studies have raised alarm among the diabetes community, as headlines proclaim that elevated A1C levels lead to cognitive decline. But while the news from theses studies is not good, it may not be as dire as some people with diabetes fear. While elevated BG does seem to impair cognitive function temporarily in one study and lead to an increased risk in dementia in another, it’s important to keep things in perspective before digging one’s cognitive grave.

In August, HealthDay reported on a study where researchers tracked over 2,000 patients, including some with diabetes, for 7 years. For people without diabetes, the researchers found that the risk of dementia increased by 10% to 18% if a person’s average blood sugar was in the range of 105 mg/dL to 115 mg/dL. For people with diabetes, the risk began to rise once average blood sugar hit above 160 mg/dL. By the time average BG reached 190 mg/dL, the risk jumped to 40%.  The researchers came to these figures after controlling for other risk factors for cognitive decline, like weight gain and inactivity.

Sounds dire, right? But in that same report, scientists said that it could have been worse. Diabetes didn’t outweigh many other known risk factors in increasing the risk of developing dementia. Here’s one researcher’s take:

“If I had diabetes and I read this study, my reaction would be relief,” said Dr. Richard O’Brien, chair of neurology at Johns Hopkins Bayview Medical Center in Baltimore, who was not involved in the research. “The effect was small.”

thnkstk_163018786_man_gears_brain_illustration_300pxIn a more recent study, as reported by NPR, researchers established the A1C levels of 141 participants without diabetes and asked them to recall a list of 15 words. What they discovered was that if a participant’s A1C ranged from 5.0 (“normal”) to 5.6 (just this side of pre-diabetic), they had slightly more trouble recalling that list of words. The researchers hypothesize that this diminished recall might come from possible blood vessel damage or disruption of glucose transport to the hippocampus, which is a part of the brain vital for memory recall.

Researchers of the more recent study said the effects of elevated A1C on cognitive decline were significant, but small. And (file under “more research is needed”) they are not making any pronouncement on whether this inability to recall 15 words is temporary or has long-term implications.

It should be noted, of course, that scientists are only just beginning to fully understand how we can improve cognitive function and stave off memory decline.  Cognitive decline is no longer considered a fait accompli, but we don’t know how much control we have. Exercise and good diet are definite keys, but less understood is the value of training on the mind.  Recently, a New York Times reporter effectively trained himself into becoming a world-renowned memory champion, for example.  So if you’re worried about cognitive decline, these studies might be a good excuse to be proactive with your mental health.

Still, these two studies don’t break as much new ground as the headlines proclaim.  What lesson should people with diabetes ultimately take away from them? The same lesson as always: controlling your BG is good and uncontrolled high BG leads to bad medical outcomes.

With so much to worry about medically, it might be best to focus on the big picture of staying healthy and to not overthink what effect diabetes might have on your thinking.

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Craig Idlebrook is a past editor for Insulin Nation, Type 2 Nation, and Información Sobre Diabetes. He is now the community engagement and content manager for T1D Exchange.

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