The brains of obese elderly people show a pattern of gray matter loss strikingly similar to that seen in early obese individuals. Alzheimer’s disease, suggests a new study. These patterns overlap in location of tissue loss but not in severity. In other words, Alzheimer’s disease patients exhibit much greater brain atrophy than cognitively healthy obese adults of similar age.
It was confirmed that “the degree of change is much lower in obesity” Philip Morris (opens in new tab), lead author of the new study and a postdoctoral fellow at McGill University Montreal Institute of Neurology. But the spatial distribution of tissue loss could help explain why obesity is a major risk factor for Alzheimer’s disease, Morys told his Live Science. Previous studies have clearly linked obesity in middle age to an increased risk of Alzheimer’s disease and other forms of dementia.
“Further evidence that this major cardiovascular risk factor for obesity is associated with evidence of neurodegeneration.” brain the cell said Dr. Jeffrey Burns (opens in new tab)co-director of the Center for Alzheimer’s Disease Research at the University of Kansas Medical Center, was not involved in the study.
However, a new study published on Tuesday (January 31) Alzheimer’s Journal (opens in new tab)it is not possible to determine the exact cause of this tissue loss, nor to identify which of the cognitively healthy and obese participants is likely to develop dementia, Burns said in Live Science. This is partly because the analysis captured only one time point in each participant’s early to mid-70s.
Related: Newer Alzheimer’s drugs slightly slow cognitive decline. Experts say it’s not a silver bullet.
“We need longitudinal, longitudinal studies that measure these things over time,” Barnes said. “How strongly is this associated with poorer future outcomes for these individuals without cognitive problems?”
Before the new study, Morys and his colleagues found evidence that obesity appears to be associated with distinct patterns of gray matter thinning in the brain in people in their 60s. Named after its color, gray matter consists of a body of brain cells, or neurons, and uninsulated wires that extend from those cells. Gray matter is found primarily in the cerebral cortex, the wrinkled outer surface of the brain.
“We found that the patterns there were very similar to what we see in Alzheimer’s disease,” Morris said of that previous study, published in 2021. Journal of Clinical Endocrinology and Metabolism (opens in new tab)To explore these similarities further, the team tapped into two huge databases of brain scans.
From the ADNI database compiled in the United States, the team pulled brain scans from people diagnosed with mild Alzheimer’s disease and healthy individuals without cognitive impairment. brain scans were compiled and grouped by body mass index (BMI), a measure used to estimate excess body fat.
In all, the team used brain scans of over 1,300 individuals to create maps of cortical thickness for people with different BMIs, and for people with and without Alzheimer’s disease. By comparing maps, we identified areas of the cortex that appeared thinner in obese and Alzheimer’s individuals, but not in lean, cognitively healthy individuals. It appeared even when people with both Alzheimer’s disease were excluded from the analysis.
“This study suggests that areas of cortical thinning seen in lean Alzheimer’s patients [Alzheimer’s disease] It is the same as the thin part of an obese person. ” Dr. Heather Ferris (opens in new tab)He is Assistant Professor of Endocrinology, Metabolism and Neuroscience at the University of Virginia (UVA) Health and was not involved in this study.
These thinned-out areas include the right temporoparietal cortex and left prefrontal cortex, which are involved in high-level cognitive functions such as long-term memory, language, attention and executive function, or the ability to plan and perform tasks. was included. Morris said. “When you look at AD patients, [problems with these functions] It’s often the first sign of illness,” he added.
But again, this study only provided a snapshot in time, so the researchers could predict whether any of the cognitively healthy, obese participants would develop dementia. And the team can’t say definitively what caused the gray matter thinning in these individuals in the first place.
Conditions Common in Obesity—such as Systemic inflammationhypertension and type 2 diabetes — can damage brain cells and is linked to Alzheimer’s-related brain changes, the researchers wrote in their report. The research team writes that there may be a mechanism at work that makes the brain thinner.
In the future, Morris and his colleagues aim to conduct large-scale clinical trials to see if weight-loss treatments can prevent subsequent cortical thinning and cognitive decline. On that front, Ferris said the big question is when to initiate such interventions.
“Many of the effects of obesity are reversed by weight loss, but disappear when nerve cells die, [is] Ferris said: “So, if weight loss is going to reduce the risk of Alzheimer’s disease, then you have to develop Alzheimer’s disease before significant brain loss occurs. That’s the case that this study can’t answer.”
