According to data, over 50 million people are currently living with dementia all over the world, and this number is expected to skyrocket to over 150 million by 2050. With such startling figures, it’s important to find ways in which to mitigate the condition, and much attention has been given to the risk factors associated with dementia so that one can better understand how to protect themselves.
Now, a recently published study has identified three major risk factors that, if addressed appropriately, can help prevent the development of dementia.
Dementia: The Big Three
A group of researchers set out to assess the genetic and modifiable risk factors associated with unhealthy brain aging. For the study, the team examined the brain scans of about 40,000 participants from the UK Biobank. They then assessed 161 modifiable risk factors for dementia, which included blood pressure, smoking, alcohol use, diet, and weight, and divided them into 15 categories to better determine which of the risk factors had the greatest impact on vulnerable brain regions.
Published in Nature Communications, the team of scientists identified three of the biggest risk factors associated with the development of dementia: type 2 diabetes, frequent alcohol intake, and air pollution by way of inhaling smog-filled air high in concentrations of nitrogen oxide.
“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 … and alcohol, of all the common risk factors for dementia,” Gwenaelle Douaud, lead researcher and an Oxford research fellow.
Dementia and Type 2 Diabetes
According to the Alzheimer’s Society, individuals living with diabetes face a 60% increased risk for developing dementia, compared to people who aren’t living with diabetes.
So, what’s the link between diabetes and dementia?
One idea is that poorly controlled diabetes can cause organs to become insulin-resistant, such as the brain. This may then lead to a build-up of amyloid and tau proteins in the brain, increasing dementia risk.
Dementia and Air Pollution
A study published in JAMA Internal Medicine found a strong association between individuals who had developed dementia and those residing in areas with higher levels of air pollution, caused by the release of fine particulate matter from agriculture and wildfires.
A separate study published earlier this year in Neurology found that individuals who were more exposed to traffic-related air pollution were more likely to have high levels of amyloid plaques – a hallmark of dementia – in their brains after they died.
The belief is that air pollution triggers inflammation in the brain, which then leads to the development of dementia. A separate theory is that the tiny particles that one inhales may circulate in the blood, before making their way to the brain and causing damage.
Dementia and Alcohol
A 2023 study published in Neurology examined the relationship between changes in alcohol consumption and dementia risk among 3 933 382 individuals in Korea. Per the findings, sustained mild drinkers had a 21% decreased risk of all-cause dementia, and sustained moderate drinkers had a 17% decreased risk of all-cause dementia compared with sustained nondrinkers, whereas sustained heavy drinkers had an 8% increased risk.
These findings add weight to the current study’s findings, which found that people who more frequently consume alcohol are more vulnerable to dementia.
Excessive alcohol consumption refers to five or more drinks on any day or 15 or more per week for men and four or more on any day or 8 or more drinks per week for women. This level of consumption can cause changes to the brain’s white matter, which handles transmitting signals and helping the body process information.
Reducing Risk
Despite the findings, Douaud and her team cautioned that the study was only observational and failed to identify causation between the risk factors identified and dementia.
In the meantime, people can make the necessary changes to their lives if they want to protect their brains as they age. Douaud advises that you eat a healthy, varied diet to help lower your blood sugar, take measures to protect against “traffic-related pollution” and drink alcohol in moderation.
“Of course, some of these should not only be down to individuals but the burden should also be shared with (local) governments devising helpful policies,” she said.
References
Christensen GM, Li Z, Liang D, Ebelt S, Gearing M, Levey AI, Lah JJ, Wingo A, Wingo T, Hüls A. Association of PM2.5 Exposure and Alzheimer Disease Pathology in Brain Bank Donors-Effect Modification by APOE Genotype. Neurology. 2024 Mar 12;102(5):e209162. doi: 10.1212/WNL.0000000000209162. Epub 2024 Feb 21. PMID: 38382009.
Jeon KH, Han K, Jeong S, et al. Changes in Alcohol Consumption and Risk of Dementia in a Nationwide Cohort in South Korea. JAMA Netw Open. 2023;6(2):e2254771. doi:10.1001/jamanetworkopen.2022.54771
Manuello, J., Min, J., McCarthy, P., Lee, S., Smith, S., Elliott, L. T., Winkler, A. M., & Douaud, G. (2024). The effects of genetic and modifiable risk factors on brain regions vulnerable to ageing and disease. Nature Communications, 15(1), 1-11. https://doi.org/10.1038/s41467-024-46344-2
Zhang B, Weuve J, Langa KM, et al. Comparison of Particulate Air Pollution From Different Emission Sources and Incident Dementia in the US. JAMA Intern Med. 2023;183(10):1080–1089. doi:10.1001/jamainternmed.2023.3300
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