April 13, 2024

Diabetes, pollution and alcohol amplify the risk of dementia

Summary: Researchers have identified key risk factors and genetic influences that affect a specific brain network vulnerable to aging, schizophrenia and Alzheimer’s disease. This “weak spot” in the brain is especially susceptible to diabetes, air pollution and alcohol consumption.

By examining 161 modifiable risk factors in more than 40,000 individuals, the study highlights the importance of a comprehensive approach to understanding the complexities of dementia. Interestingly, the research also discovered a link to XG blood group antigens and genes shared by the X and Y chromosomes, opening new avenues for genetic exploration in dementia.

Key facts:

  1. Vulnerable brain network: This study identifies a brain network that is crucially affected by aging and diseases such as schizophrenia and Alzheimer’s disease, showing greater susceptibility to specific lifestyle and environmental factors.
  2. Main risk factors identified: Among the modifiable risk factors examined, diabetes, traffic-related air pollution and alcohol consumption were found to have the most significant impact on the brain’s vulnerable network.
  3. Genetic information revealed: Research has uncovered genetic associations with dementia, including links to cardiovascular disease and the XG blood group system, highlighting underexplored areas of the genome.

Source: University of Oxford

Researchers had previously identified a “weak spot” in the brain, which is a specific network of higher-order regions that not only develop later during adolescence, but also show earlier degeneration in old age.

They showed that this brain network is also particularly vulnerable to schizophrenia and Alzheimer’s disease.

In this new study, published in Nature CommunicationsThey investigated the genetic and modifiable influences on these fragile brain regions by looking at brain scans of 40,000 UK Biobank participants aged over 45.

Researchers examined 161 risk factors for dementia and ranked their impact on this vulnerable brain network, beyond the natural effects of age. Credit: Neuroscience News

Researchers examined 161 risk factors for dementia and ranked their impact on this vulnerable brain network, beyond the natural effects of age.

They classified these so-called “modifiable” risk factors – as they can potentially be changed throughout life to reduce the risk of dementia – into 15 broad categories: blood pressure, cholesterol, diabetes, weight, alcohol consumption, smoking, mood depressive, inflammation. , pollution, hearing, sleep, socialization, diet, physical activity and education.

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 show that these specific parts of the brain are most vulnerable to diabetes, traffic-related diseases air pollution – increasingly an important factor in dementia – and alcohol, of all common risk factors for dementia.’

“We discovered that several variations in the genome influence this brain network and 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 a totally new and unexpected discovery.’

Professor Lloyd Elliott, co-author from Simon Fraser University in Canada, agrees: “In fact, two of our seven genetic discoveries are located in this specific region that contains the XG blood group genes, and this region is highly atypical because it is shared by X and Y sex chromosomes.

“This is actually quite intriguing, as we don’t know much about these parts of the genome; our work shows that there are benefits to exploring this genetics further terra incognito.’

Importantly, as Professor Anderson Winkler, co-author from the National Institutes of Health and the University of Texas Rio Grande Valley in the USA, highlights: ‘What makes this study special is that we examined the unique contribution of each modifiable risk factor, looking at all of them together to assess the degeneration resulting from this specific brain “weak spot”.

“It is with this kind of comprehensive and holistic approach – and after taking into account the effects of age and gender – that three emerged as the most harmful: diabetes, air pollution and alcohol.”

This research sheds light on some of the most critical risk factors for dementia and provides new information that may contribute to prevention and future strategies for targeted interventions.

About this Alzheimer’s disease and genetic research news

Author: Christopher McIntyre
Source: University of Oxford
Contact: Christopher McIntyre – University of Oxford
Image: Image is credited to Neuroscience News

Original research: Free access.
“The effects of genetic and modifiable risk factors on brain regions vulnerable to aging and disease” by Gwenaëlle Douaud et al. Nature Communications


Abstract

The effects of genetic and modifiable risk factors on brain regions vulnerable to aging and disease

We previously identified a network of higher-order brain regions particularly vulnerable to the aging process, schizophrenia and Alzheimer’s disease.

However, it is not yet known what the genetic influences are on this fragile brain network and whether it can be altered by the most common modifiable risk factors for dementia.

Here, in nearly 40,000 UK Biobank participants, we show for the first time significant genome-wide associations between this brain network and seven gene clusters implicated in cardiovascular deaths, schizophrenia, Alzheimer’s and Parkinson’s diseases, and with the two antigens of blood group XG located in the pseudoautosomal region of the sex chromosomes.

We further reveal that the most deleterious modifiable risk factors for this vulnerable brain network are diabetes, nitrogen dioxide – a proxy for traffic-related air pollution – and frequency of alcohol consumption.

The extent of these associations was uncovered by examining these modifiable risk factors in a single model to assess the unique contribution of each to the vulnerable brain network, above and beyond the dominant effects of age and sex.

These results provide a comprehensive picture of the role played by genetic and modifiable risk factors in these fragile parts of the brain.

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