New study reveals risk factors for faster brain aging

Researchers find that diabetes, air pollution and alcohol intake are the most harmful out of 15 modifiable risk factors for dementia.

In a new study, researchers from the Nuffield Department of Clinical Neurosciences at the University of Oxford have uncovered insights into the modifiable risk factors for dementia. Drawing on data from UK Biobank participants, the study identified diabetes, traffic-related air pollution, and alcohol intake as the most detrimental factors among 15 modifiable risks.

Previous research from the same team had pinpointed a vulnerable area in the brain – a network of higher-order regions susceptible to degeneration with age. This network, which matures later during adolescence, is also implicated in conditions like schizophrenia and Alzheimer’s disease. Building on this knowledge, the recent study, published in Nature Communications, investigated genetic and modifiable influences on these fragile brain regions.

Longevity.Technology: Analyzing brain scans from over 40,000 UK Biobank participants aged over 45, the researchers examined 161 potential risk factors for dementia. They ranked these factors based on their impact on the vulnerable brain network, accounting for the natural effects of aging. The identified modifiable risk factors spanned a range of domains, from physiological markers like blood pressure and cholesterol to lifestyle factors such as diet, education, physical activity, and socialization [1].

One striking finding of the study is the significant role played by environmental factors in accelerating cognitive decline. Traffic-related air pollution emerged as a particularly potent risk factor, highlighting the pervasive impact of our surroundings on brain health. As urbanization and industrialization continue to shape our environments, addressing air quality becomes imperative not only for respiratory health but also for preserving cognitive function and reducing dementia risk.

Importantly, the study underscores the profound influence of lifestyle choices on longevity and healthspan. Alcohol consumption, when excessive, emerged as a notable risk factor for dementia – a reminder of the importance of moderation when trying to increase healthspan and maintain brain health. Likewise, factors like diet, exercise, and sleep patterns can either bolster cognitive resilience or contribute to cognitive decline over time.

Professor Gwenaëlle Douaud, who led this study, said: “We know that a constellation of brain regions degenerates earlier in aging, and in this new study we have shown that these specific parts of the brain are most vulnerable to diabetes, traffic-related air pollution − increasingly a major player in dementia − and alcohol, of all the common risk factors for dementia.

“We have found that several variations in the genome influence this brain network, and they are implicated in cardiovascular deaths, schizophrenia, Alzheimer’s and Parkinson’s diseases, as well as with the two antigens of a little-known blood group, the elusive XG antigen system, which was an entirely new and unexpected finding [2].”

New study reveals risk factors for faster brain aging
To the left of the figure, the red-yellow colour denotes the regions that degenerate earlier than the rest of the brain, and are vulnerable to Alzheimer’s disease. These brain areas are higher-order regions that process and combine information coming from our different senses. To the right of the figure, each dot represents the brain data from one UK Biobank participant. The overall curve shows that, in these particularly fragile regions of the brain, there is accelerated degeneration with age.

Professor Lloyd Elliott, a co-author from Simon Fraser University in Canada, agreed. “In fact, two of our seven genetic findings are located in this particular region containing the genes of the XG blood group, and that region is highly atypical because it is shared by both X and Y sex chromosomes,” he said. “This is really quite intriguing as we do not know much about these parts of the genome; our work shows there is benefit in exploring further this genetic terra incognita [2].”

Professor Anderson Winkler, a co-author from the National Institutes of Health and The University of Texas Rio Grande Valley in the US, pointed out that the study was special because it “examines the unique contribution of each modifiable risk factor by looking at all of them together to assess the resulting degeneration of this particular brain ‘weak spot’.”

“It is with this kind of comprehensive, holistic approach − and once we had taken into account the effects of age and sex − that three emerged as the most harmful: diabetes, air pollution, and alcohol,” he added [2].

While genetic predispositions undoubtedly play a role in dementia risk, the study emphasizes the modifiability of many risk factors. By identifying and addressing these factors early in life, individuals can potentially mitigate their risk of developing dementia later on. This highlights the importance of public health initiatives aimed at promoting healthy behaviors and environments conducive to cognitive well-being across the lifespan.

Despite advancements in our understanding of dementia risk factors, there remains a significant global unmet need in dementia care. As populations age worldwide, the prevalence of dementia is expected to rise, placing a growing burden on healthcare systems and caregivers. Addressing this challenge requires not only continued research into preventive strategies but also improvements in dementia diagnosis, treatment and support services.

The study sheds light on the modifiable risk factors for dementia, offer insights into avenues for prevention and intervention. By fostering understanding of risks in our surroundings, addressing environmental influences and promoting healthy lifestyles, proactive steps can be taken towards preserving cognitive function and enhancing overall healthspan and quality of life as we age.

[1] https://www.nature.com/articles/s41467-024-46344-2
[2] https://www.ox.ac.uk/news/2024-03-27-risk-factors-faster-aging-brain-revealed-new-study

Image credit: G Douaud and J Manuello