Do glucose levels affect cognitive performance in people with type 1 diabetes? Study finds out

The study published in the journal npj Digital Medicine revealed that cognition was slower in moments when glucose was atypical – that is, considerably higher or lower than someone’s usual glucose level. However, some people were more susceptible to the cognitive effects of large glucose fluctuations than others.

T1D is an autoimmune disease characterized by glucose variability. Previous laboratory studies have shown that very low and very high glucose levels impair cognitive function. However, technological limitations made it difficult to study the impact of naturally occurring glucose fluctuations on cognition outside of the laboratory, preventing researchers from obtaining repeated, high-frequency measurements within the same individuals over time. High-frequency measurements are necessary to understand whether glucose fluctuations impact cognition similarly for everyone.

In the study, researchers collected high-frequency glucose and cognitive data from 200 individuals with T1D using digital glucose sensors and smartphone-based tests. Glucose levels were measured every five minutes, and cognitive assessments were conducted three times daily for fifteen days. This data collection allowed researchers to analyze the cognitive effects of natural glucose fluctuations. Utilizing machine learning, they investigated individual differences in the impact of glucose on cognition.

The results showed that cognitive function was impaired when glucose was considerably higher or lower than usual. The researchers also found that people differed from each other in terms of how much glucose fluctuations impacted their cognitive speed, and some people – including older adults and adults with certain health conditions – were much more impacted by glucose fluctuations than others.

“Our results demonstrate that people can differ a lot from one another in how their brains are impacted by glucose. We found that minimizing glucose fluctuations in daily life is important for optimizing processing speed, and this is especially true for people who are older or have other diabetes-related health conditions,” said Laura Germine, PhD, co-senior author of the paper and director of McLean’s Laboratory for Brain and Cognitive Health Technology.

Reference: Z. W. Hawks, E. D. Beck, L. Jung, L. M. Fonseca, M. J. Sliwinski, R. S. Weinstock, E. Grinspoon, I. Xu, R. W. Strong, S. Singh, H. P. A. Van Dongen, M. R. Frumkin, J. Bulger, M. J. Cleveland, K. Janess, Y. C. Kudva, R. Pratley, M. R. Rickels, S. R. Rizvi, N. S. Chaytor & L. T. Germine; Dynamic associations between glucose and ecological momentary cognition in Type 1 Diabetes; Journal: npj Digital Medicine; DOI: 10.1038/s41746-024-01036-5