(HealthDay News) – Lower hemoglobin A1c (HbA1c) and blood glucose levels are associated with better memory performance in healthy, older adults, according to a study published online Oct. 23 in Neurology.

Lucia Kerti, from Charité-University Medicine in Berlin, and colleagues examined the correlation between HbA1c and glucose levels on memory performance and hippocampal volume and microstructure in a cohort of 141 individuals without diabetes (72 women; mean age, 63.1 years). Memory was tested using the Rey Auditory Verbal Learning Test, and peripheral levels of fasting hemoglobin A1c, glucose, and insulin were assessed. Hippocampal volume and microstructure were assessed as indicated by gray matter barrier density on 3-tesla magnetic resonance imaging scans.

The researchers found that there were significant correlations for lower HbA1c and glucose levels with better scores in delayed recall, learning ability, and memory consolidation. A strong correlation remained for HbA1c with memory performance, even in multiple regression models. The beneficial effects of lower HbA1c on memory were partially mediated by hippocampal volume and microstructure.

“Our results indicate that even in the absence of manifest type 2 diabetes mellitus or impaired glucose tolerance, chronically higher blood glucose levels exert a negative influence on cognition, possibly mediated by structural changes in learning-relevant brain areas,” the authors conclude.

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