Risk Factors For Faster Brain Aging

Previous research from this group revealed an area of weakness in the brain of a specific network of higher-order regions that only develop later in adolescence but also display earlier degeneration in old age, and they showed that this brain network is particularly vulnerable to Alzheimer’s disease and schizophrenia. This study investigated genetic and modifiable influences on these regions by utilizing data from the UK Biobank.

This study examined 161 risk factors for dementia by analyzing brain scans of 40,000 people over the age of 45 years old. The modifiable risk factors were ranked by their impact on the vulnerable brain network over and above the natural effects of aging, classifying them into 15 broad categories: blood pressure, diabetes, weight, cholesterol, smoking, inflammation, hearing, sleep, diet, physical activity, education, socialism, pollution, alcohol consumption, and depressive mood.

 “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,” said Prof. Gwenaëlle Douaud, who led this study.

“'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,” added Douaud.

“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. 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,” said Prof. Lloyd Elliott, a co-author from Simon Fraser University in agreement. 

“What makes this study special is that we examined 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,” noted Prof. Anderson Winkler, a co-author from the National Institutes of Health and The University of Texas Rio Grande Valley.