Man Checking Blood Sugar Level With Glucometer

(© Andrey Popov -

LONDON — Prediabetes, or having elevated blood sugar levels without developing diabetes symptoms, can be a tricky condition to navigate. Like patients with type 2 diabetes, these individuals typically watch their diets and may need medication to maintain their levels. While their attention may focus on preventing diabetes, a new study finds people with high blood sugar may also be at risk for developing dementia too.

Researchers from University College London (UCL) say people with elevated blood sugar are 42 percent more likely to suffer from mental decline. They are also at a 54-percent higher risk of developing full-blown dementia.

While having higher than normal levels of blood sugar does not automatically classify someone as diabetic, it means they are more at risk of developing type 2 diabetes. According to the Centers for Disease Control and Prevention, around 88 million American adults have prediabetes. Stunningly, about 84 percent of these people don’t know they have it.

What kind of dementia does prediabetes cause?

Researchers analyzed data on 500,000 British adults with an average age of 58 in this study. Each participant received a blood test and then completed a series of memory tests. Researchers discovered that prediabetes has a link to higher risks for vascular dementia. This is a common form of dementia caused by reduced blood flow to the brain.

People with diabetes, meanwhile, are three times more likely to develop vascular dementia than people with normal blood sugar levels. These patients are also more likely to develop Alzheimer’s disease, the most common form of dementia.

“Our research shows a possible link between higher blood sugar levels – a state often described as ‘prediabetes’ – and higher risks of cognitive decline and vascular dementia,” lead author Dr. Victoria Garfield of UCL’s Institute of Cardiovascular Science says in a university release. “Previous research has found a link between poorer cognitive outcomes and diabetes but our study is the first to investigate how having blood sugar levels that are relatively high – but do not yet constitute diabetes – may affect our brain health.”

“In this relatively young age group, the risks of cognitive decline and of dementia are very low; the excess risks we observe in relation to elevated blood sugar only modestly increase the absolute rates of ill health. Seeing whether these effects persist as people get older, and where absolute rates of disease get higher, will be important,” senior author Professor Nishi Chaturvedi adds.

“Our findings also need to be replicated using other datasets. If they are confirmed, they open up questions about the potential benefits of screening for diabetes in the general population and whether we should be intervening earlier.”

How does diabetes damage the brain?

Among the 35,418 participants who underwent MRI brain scans, researchers find that prediabetes has a link to a smaller hippocampus. This part of the brain handles both learning and memory functions. High blood sugar also appears to have a strong connection with lesions on the brain. However, the research team believes these symptoms could be more closely associated with high blood pressure than diabetes.

The findings appear in the journal Diabetes, Obesity and Metabolism.

SWNS writer William Janes contributed to this report.

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