AI Identifies Aging Factors in Human Brains

Inflammation, glucose levels, and activity levels influence brain aging.

Reviewed by Hara Estroff Marano

Is your brain younger than its biological age? Medical researchers at the Karolinska Institutet at Stockholm, Sweden, have published a new study demonstrates how an artificial intelligence (AI) tool identifies contributing factors to accelerated brain aging.

“The brain age gap (BAG), derived from differences between an individual's predicted brain age (PBA) and chronological age (CA), can serve as a valuable biomarker of brain health,” a team led by Anna Marseglia ireported in the journal Alzheimer's & Dementia published by the Alzheimer’s Association. t

Using the brain age gap as a potential digital biomarker of brain resiliency. the Swedish research team evaluated the impact of neurodegenerative disease; vascular disease[ lifestyle factors such as activity and diet; cardiometabolic (CMD) risk factors and disorders such as heart disease, diabetes, obesity, and hypertension; biological processes such as inflammation, and disruption in glucose and lipid metabolism. Additionally, the team studied the link between the brain age gap and cognitive functioning and looked for potential differences between biological females and males as defined at birth.

The data used for the study included 739 Gothenburg residents, age 70, who participated in a Swedish population-based cohort study from 2014 to 2016. All had undergone brain imaging that passed neuroimaging quality control standards and were free of neurological disorders such as dementia.

“Advancements in artificial intelligence facilitated the development of brain age models using the whole structural magnetic resonance imaging (MRI), capturing the resilience's core biological dimension,” the researchers wrote.

The brain scans of the participants were analyzed by AI trained on more than 18,800 MRI images from seven other cohorts. Their AI model output brain age gap scores derived from the difference between an individual's brain biological age and their chronological age. The older-looking the brain, the larger the gap.

Brains with older appearance and larger gaps were associated with high levels of inflammation, glucose, and cerebrovascular burden. The older-looking brains were linked to low levels of physical activity, presence of stroke/TIA, and diabetes.

Interestingly, among the obese who were regularly physically active, the brain age gap score was lower. A feature of younger-looking brains was greater cortical thickness.

“Notably, sex-specific associations emerged, suggesting distinct pathological and resilience pathways to cognitive disorders between females and males,” the researchers noted.

Older-looking female brains were linked to alcohol risk consumption and lower episodic memory. In men, older-looking brains was linked to diminished cortical thickness and cognitive function in the areas of attention/speed, visuospatial abilities, and verbal fluency.

“The interplay between vascular brain injury, inflammation, and insulin-related dysregulations may be the key to understanding the neurobiological underpinnings of BAG, therefore, of resilience mechanisms in aging,” conclude the researchers.

Harnessing the pattern-recognition capabilities of AI, researchers were able to pinpoint factors from complex brain images to reveal important health findings. This research highlights the impact of physical activity, obesity, stroke, inflammation, cerebrovascular disease on the brain’s biological age, as well as the differences between female and male brains. the brain age gap has potential to serve as a digital biomarker of brain resilience.

“Favorable lifestyles, like physical activity, may help preserve brain integrity, thus younger-looking brains,” reported the researchers.

Based on their conclusions, the Karolinska Institutet scientists suggest that future studies conducted over an extended period of time should take into account the differences between female and male brains,and examine the interplay and impact of inflammation, glucose metabolism, vascular brain injury, and cardiometabolic disorders on both cognitive functioning and the brain age gap.

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