High-Normal Blood Glucose Tied To Brain Shrinkage

In the US, the "high-normal" blood glucose referred to in this study falls under the category of Impaired Fasting Glucose (IFG) or pre-diabetes. Fasting glucose is usually part of a blood test taken in the morning after an overnight fast and IFG is defined as a BG of 100 to 125 mg/dl. (I think they're calling it "normal" because they're using the World Health Organization's criteria of 110 mg/dl.) There's another pre-diabetic state that shows up as Impaired Glucose Tolerance (IGT) but since the test is done at precise times after eating, it's not as frequently employed.

A staggering number of people have these prediabetic conditions - 35% of those 20 years or older, and 50% of those 65 or older. Affecting nearly 80 million people, prediabetes overshadows the prevalence of diabetes proper.

And prediabetes is not benign, as this one study shows. A high fasting glucose, but still less than 110 mg/dl, was associated with an up to 10% loss of brain volume in the areas of the hippocampus and the amygdala. These areas govern memory, behavior, thinking, and spacial understanding:

Higher Normal Fasting Plasma Glucose Is Associated With Hippocampal Atrophy, Neurology, 4 September 2012

"These findings suggest that even in the subclinical range and in the absence of diabetes, monitoring and management of plasma glucose levels could have an impact on cerebral health. If replicated, this finding may contribute to a reevaluation of the concept of normal blood glucose levels and the definition of diabetes."

From Wikipedia/Amygdala:
"Research using Rorschach test blot 03 (shown below) finds that the number of "unique responses" to this random figure links to larger sized amygdalae."


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