Johns Hopkins University-led researchers, working with the Biomarkers for Older Controls at Risk for Dementia (BIOCARD) cohort, have found that certain factors are linked to faster brain shrinkage and quicker progression from normal thinking abilities to mild cognitive impairment (MCI). People with type 2 diabetes and low levels of specific proteins in their cerebrospinal fluid showed more rapid brain changes and developed MCI sooner than others.
Long-term studies tracking brain changes over many years are rare but valuable. Previous research mostly provided snapshots in time, which can't show how individual brains change over the years. By following participants for up to 27 years (20-year median), this study offers new insights into how health conditions might speed up brain aging.
In a study, "Acceleration of Brain Atrophy and Progression From Normal Cognition to Mild Cognitive Impairment," published in JAMA Network Open, researchers used the BIOCARD cohort to examine risk factors associated with the acceleration of brain atrophy and progression from normal cognition to MCI. An Invited Commentary is also available.
BIOCARD was initiated at the National Institutes of Health in 1995 and continued at Johns Hopkins University from 2015 to 2023. A total of 185 participants, averaging 55 years old at the start and all cognitively normal, were selected. They underwent brain scans and tests of their cerebrospinal fluid over 20 years, measuring changes in brain structures and levels of proteins associated with Alzheimer's disease.
Findings showed that high rates of white matter shrinkage and enlargement of the brain's ventricles (fluid-filled spaces) were significant predictors of earlier MCI onset. Specifically, white matter atrophy was associated with an 86% higher risk and ventricular enlargement with a 71% higher risk of progressing to MCI.
Individuals with diabetes showed an average 41% higher risk of progressing from normal cognition to MCI compared to individuals without.
A low ratio of amyloid β peptides Aβ42 to Aβ40 in cerebrospinal fluid was associated with a 48% higher risk of developing MCI. This ratio acts as a biomarker for Alzheimer's disease, where an imbalance between these two forms of amyloid beta proteins is linked to the formation of harmful plaques in the brain.
When participants had both diabetes and a low Aβ42 to Aβ40 ratio, their risk of progressing to MCI increased by 55%, demonstrating that these two factors together significantly heighten the likelihood of cognitive decline.
These results support the importance of early identification of individuals exhibiting accelerated brain atrophy and certain unfavorable biomarkers. By recognizing when higher risk is present, preventive intervention strategies can be optimized to delay or hopefully even prevent the onset of MCI.
Long-term longitudinal studies like the current one are essential to deepen the understanding of how these factors interact and influence the aging brain.
More information: Study: Yuto Uchida et al, Acceleration of Brain Atrophy and Progression From Normal Cognition to Mild Cognitive Impairment, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.41505
Invited Commentary: Shohei Fujita, Optimizing Strategies to Prevent Cognitive Decline With 20-Year Brain Imaging, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.41466
https://medicalxpress.com/news/2024-11-indicators-aging-brain-year.html
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