There is a growing body of research linking high blood sugar with decreased memory performance in both animal and human subjects. Adding to these data, a new study published online in the Oct. 23 issue of Neurology set out to measure the effect of blood sugar on memory and hippocampal volume in healthy, older adults. In this cross-sectional analysis, Agnes Flöel, MD, of Charité University Medicine in Berlin, Germany, and colleagues found that “chronically higher blood glucose levels exert a negative influence on cognition, possibly mediated by structural changes in learning-relevant brain areas.”
Investigators tested 141 individuals (72 women, mean age 63.1 years) for memory performance using the Rey Auditory Verbal Learning Test. They also measured peripheral levels of fasting HbA1c, glucose, and insulin and performed MRI scans to assess hippocampal volume and microstructure.
They found that lower performances in all 3 memory tasks (delayed recall, learning ability, consolidation) were associated with higher levels of both the long-term marker of glucose control, HbA1c, and the short-term marker glucose. For insulin, the correlations were less clear, they wrote. They also found that higher levels of HbA1c and glucose also correlated with decreased volume and microstructure of the hippocampus.
“The present findings might lead to a better understanding of the mechanisms underlying the effect of chronically elevated glucose brain function and structure, and the interaction between these factors,” Dr. Flöel and colleagues wrote. These results suggest that using strategies to reduce glucose levels may benefit older individuals, but this must be further examined in future interventional trials, they concluded.
See Neurology Now's previous coverage of blood sugar and cognition: http://bit.ly/18CGdrc.