Diabetes can lead to a reduction in cognitive function by promoting neurodegeneration — the destruction of neurons (nerve cells) in the brain — independently of certain other ways that diabetes can affect the brain, according to a new analysis published in the journal Neurology.
Researchers have long known that diabetes increases the risk of cognitive decline, but they haven’t known exactly how diabetes is linked to cognitive function. Any disruption of the brain’s normal function — whether it’s caused by cardiovascular problems affecting the supply of blood and oxygen to parts of the brain, or by a reduced ability to send electrical signals from one neuron to another — can lead to impaired cognition. For the latest analysis, researchers were interested in looking at three different potential markers of cognitive decline in people with diabetes — small blood vessel disease, neurodegeneration, and biomarkers (such as blood markers) of Alzheimer’s disease.
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The subjects of the analysis were participants in the MEMENTO study, which looked at French adults who were recruited in memory clinics and screened for cognitive problems. Participants were designated as having diabetes based on self-reporting, blood glucose testing, or medical records showing use of a drug to treat diabetes. All participants underwent extensive brain-related tests and measurements, and mathematical modeling was used to look at whether markers of small vessel disease, neurodegeneration, or Alzheimer’s disease played an intermediate role between diabetes status and cognitive function, as measured by five neuropsychological tests.
Neurodegeneration linked to changes in cognitive function
Overall, 254 participants, or 11.1% of those in the study, had diabetes, and had an average age of 71.6. After adjusting for factors other than diabetes status that could affect cognitive function, the researchers found that the link between diabetes status and cognitive function was significantly affected by measures of neurodegeneration (such as mean cortical thickness, parenchymal fraction, and hippocampal volume within the brain). This relationship was not significantly affected by measures of small vessel disease or Alzheimer’s disease. What’s more, similar results were seen when the researchers looked not at overall cognitive function, but specifically at memory and executive functioning.
Based on these results, the researchers concluded that the effect of having diabetes on cognitive function could be explained by neurodegeneration alone, independently of other disease processes. This information may help researchers and doctors explore ways to help prevent or treat cognitive impairment in older people with diabetes. More studies across different populations are needed, the researchers wrote, to confirm these findings and gain a better understanding of what mechanisms lead to cognitive changes in people with diabetes.
Want to learn more about maintaining cognitive health with diabetes? Read “Nine Tips to Keep Your Memory With Diabetes,” “Keeping Your Brain Strong With Diabetes” and “Memory Fitness: How to Get It, How to Keep It.”
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