Type 2 diabetes found to speed up brain aging and cognitive decline
Comparing those with type 2 diabetes and those without, a new study published in the journal eLife has found the disease significantly accelerates brain aging. While the pattern of neurodegeneration is similar to normal brain aging, it was found to progress around 26 percent faster in those with the largely preventable disease.
For the first-of-its-kind study, the researchers drew on a dataset from the UK Biobank, specifically brain structure and function data for 20,000 people aged 50 to 80 years old. Using this data and comparing the results with a meta-analysis of almost 100 other studies, the team was able to distinguish between normal age-related brain and cognitive changes, and those specific to type 2 diabetes.
They found that changes to executive functions such as working memory, learning, flexible thinking and self-control, and declines in brain processing speed, were common for both those with and without diabetes. However, the former group saw an additional 13.1-percent decrease in executive function and an extra 6.7-percent decrease in processing speed compared to those of the same age without diabetes.
When the team used MRI scans to analyze brain structure and activity, as expected they found gray brain matter decreased with age, with the biggest decrease in the ventral striatum – a brain region critical for executive functions. But those with diabetes suffered an additional 6.2 percent decrease of gray matter in this brain region, as well as decreases in other regions.
The findings suggest there is a strong correlation between normal age-related neurodegeneration and type 2 diabetes-related neurodegeneration, but that the disease significantly speeds up cognitive decline. Also, the greater the duration of diabetes, the more pronounced the effects on brain function, with the study linking the progression of diabetes with around a 26-percent acceleration of brain aging. While the mechanisms responsible for the effects of the disease on the brain aren’t known, the researchers do offer a hypothesis.
"Our findings suggest that type 2 diabetes and its progression may be associated with accelerated brain aging, potentially due to compromised energy availability causing significant changes to brain structure and function," said Lilianne Mujica-Parodi, senior author of the study and Director of the Laboratory for Computational Neurodiagnostics, Stony Brook University.
She added that the results also suggest that the brain may have already undergone significant structural damage due to type 2 diabetes before it has been formally diagnosed, so there needs to be more work done to identify brain-based biomarkers for the disease, as well as treatment strategies that target its neurocognitive effects.
First author of the study Botond Antal reinforced this view, saying, "Routine clinical assessments for diagnosing diabetes typically focus on blood glucose, insulin levels and body mass percentage. However, the neurological effects of type 2 diabetes may reveal themselves many years before they can be detected by standard measures, so by the time type 2 diabetes is diagnosed by conventional tests, patients may have already sustained irreversible brain damage.”
The team’s study appears in the journal eLife.