Researchers Identify Key Factors In Brain Aging

Researchers Identify Key Factors In Brain Aging

Diabetes, traffic-related air pollution, and the frequency of alcohol consumption are the most harmful risk factors for dementia, according to a new study published in Nature Communications.

An international team of researchers analyzed how certain modifiable risk factors for dementia affect regions in the brain that are already prone to schizophrenia and Alzheimer’s disease. These regions in the brain develop during adolescence but deteriorate as people age, which is why the researchers described this part of the brain as a “weak spot.”

For the study, the scientists looked at brain scans of 39,676 participants in the U.K. Biobank. Participants were between the ages of 44 and 83, and a few had been diagnosed with dementia. The researchers examined 161 risk factors and ranked them according to their impact on these vulnerable regions of the brain, over and above the natural effects of age.

Some of the risk factors were genetic or “non-modifiable,” while others were “modifiable,” meaning that they have the potential to be changed throughout life to reduce the risk of dementia. The scientists then classified the modifiable risk factors into 15 broad categories:

  • Alcohol consumption
  • Blood pressure
  • Cholesterol
  • Depressive mood
  • Diabetes
  • Diet
  • Education
  • Hearing
  • Inflammation
  • Physical activity
  • Pollution (the amount of nitrogen oxide in the air)
  • Sleep
  • Smoking
  • Socialization
  • Weight

Gwenaëlle Douaud, an associate professor at Oxford University in Oxford, England, who led the study, pointed out that diabetes, air pollution, and alcohol intake had an effect nearly twice as much as the other leading factors. Following the three most detrimental factors were sleep, weight, smoking, and blood pressure.

When examining the non-modifiable factors, the research team identified seven genetic clusters that affect these vulnerable parts of the brain, some of which are also associated with cardiovascular deaths, schizophrenia, Parkinson’s disease, and Alzheimer’s disease. Douaud said the genetic and modifiable risk factors are not comparable.

Among the seven clusters, the scientists found two antigens of a little-known blood group called the “X.G. antigen system.” This was an “entirely new and unexpected finding,” Douaud said in a press release.

Lloyd Elliott, a co-author of the study and an assistant professor at Simon Fraser University in British Columbia, Canada, agreed. “This is quite intriguing as we do not know much about these parts of the genome,” Elliott said in a press release.

Dr. Logan DuBose, a resident physician at George Washington University who was not involved in the study, also noted the importance of the X.G. gene and how it may affect the brain’s “weak spot.”

“Interestingly, they discovered that individuals with a specific type of X.G. gene could be more affected by air pollution found in the air they breathe,” Dr. DuBose told Medical News Today. “This was found to be a major factor contributing to damage in fragile brain areas.”

According to Dr. Dubose, this finding is significant “as it could establish a link between environmental factors such as living in high-traffic areas or large cities with lots of pollution and increased risk of damage to fragile brain regions.”

Dr. Dubose emphasized the importance of discovering that there is a genetic influence on a person’s susceptibility to known risk factors.

“This insight is crucial, especially as technology advances our ability to know a person’s genetic predispositions,” Dr. Dubose told Medical News Today. “Knowing a person’s genes and the associated risks those genes cause allows healthcare providers and patients to intervene early, potentially slowing disease progression or damage that otherwise would be more accelerated.”

Dr. Claire Sexton, the senior director of scientific programs and outreach at the Alzheimer’s Association, told Medical News Today that traffic-related air pollution, along with diabetes and frequency of alcohol consumption, are already well-known risk factors for dementia, so their connection with a “vulnerable brain network seems very plausible.”

Still, Sexton, who was not involved in the study, called for more research in representative populations that may replicate and confirm the study’s findings. As an example, Dr. Sexton mentioned the U.S. Pointer Study, the Alzheimer’s Association’s two-year trial, to evaluate “whether lifestyle interventions that simultaneously target multiple risk factors can protect cognitive function in older adults at increased risk for cognitive decline.”

The first such study of a large, representative group of Americans

The study, involving more than 2,000 volunteers, is the first such study of a large, representative group of Americans.

“Nearly 30 percent of current participants are from populations historically underrepresented in Alzheimer’s/dementia research,” Dr. Sexton told Medical News Today. “Data/results are expected in 2025.”

Meanwhile, what made the most recent study special was examining the “unique contribution” of each modifiable risk factor, then looking at all of them together to assess how they impact the degeneration of the brain’s “weak spot,” Anderson Winkler, the study’s co-author from the National Institutes of Health and a professor at the University of Texas Rio Grande Valley, said in a press release.

According to the researchers, their study “sheds light on some of the most critical risk factors for dementia and provides novel information that can contribute to prevention and future strategies for targeted intervention.”

More than 55 million people worldwide are living with dementia, a progressive disorder that destroys nerve cells damages the brain, and affects memory, thinking, and the ability to perform daily activities, according to the World Health Organization (WHO). The most common type of dementia is Alzheimer’s disease, which the WHO says may contribute to 60 to 70 percent of dementia cases. The Alzheimer’s Association reports that nearly seven million people in the United States have dementia.

There is no cure for dementia, but according to WHO, people with the disease can maintain their quality of life and promote their well-being by 
being physically active, taking part in activities and social interactions that stimulate the brain and maintain daily function, and taking medications that help with dementia symptoms.

Source Links:

https://www.medicalnewstoday.com/articles/researchers-identify-brain-aging-factors-dementia-risk#Studying-the-brains-weak-spot
https://www.nature.com/articles/s41467-024-46344-2
https://www.ox.ac.uk/news/2024-03-27-risk-factors-faster-aging-brain-revealed-new-study-0
https://www.who.int/news-room/fact-sheets/detail/dementia
https://www.alz.org/alzheimers-dementia/facts-figures#

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