Previous research has shown that obesity is linked with Alzheimer's disease (AD)-related changes, such as cerebrovascular damage and amyloid-β accumulation. However, to date no research has made a direct comparison between brain atrophy patterns in AD and obesity.

Using a sample of over 1,300 individuals, the researchers compared patterns of grey matter atrophy in obesity and AD. They compared the AD patients with healthy controls, and obese with non-obese individuals, creating maps of grey matter atrophy for each group.

The scientists found that obesity and AD affected grey matter cortical thinning in similar ways. For example, thinning in the right temporo-parietal cortex and left prefrontal cortex were similar in both groups. Cortical thinning may be a sign of neurodegeneration. This suggests that obesity may cause the same type of neurodegeneration as found in people with AD.

Obesity is increasingly recognized as a multisystem disease affecting respiratory, gastrointestinal, and cardiovascular systems, among others. Published in theJournal of Alzheimer's Diseaseon Jan. 31, 2022, this study helps reveal a neurological impact as well, showing obesity may play a role in the development of Alzheimer's and dementia.

"Our study strengthens previous literature pointing to obesity as a significant factor in AD by showing that cortical thinning might be one of the potential risk mechanisms," says Filip Morys, a PhD researcher at The Neuro and the study's first author. "Our results highlight the importance of decreasing weight in obese and overweight individuals in mid-life, to decrease the subsequent risk of neurodegeneration and dementia."

This study was funded with a Foundation Scheme award to AD from the Canadian Institutes of Health Research, computing resources from Calcul Quebec and Compute Canada, and by a postdoctoral fellowship from Fonds de Recherche du Québec -- Santé.