Researchers at Western University in Canada conducted a large meta-analysis (combining the results of multiple scientific studies) to see if there is a link between traffic-related air pollution and Dementia. The results were rather disconcerting.
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As noted in many of our previous articles, Dementia is on the rise worldwide. According to the WHO, over 55 million people are living with this terrible condition right now, with almost 10 million new cases each year.
A meta-analysis with data from over 90 million people
Above mentioned statistics are a significant driver for scientists to conduct research to see if we can learn more about the condition and whether we can prevent or even cure it.
Suggested reading:
Keeping your brain lively with games may defer Alzheimer's Dementia for several years (Universal-Sci)
What is the difference between Alzheimer's disease and Dementia? (Universal-Sci)
Reason enough for researchers at the Canadian Western University to investigate the influence of air pollution on Dementia (specifically particulate matter with a diameter smaller than 2.5 micrometers or PM2.5). The team conducted a meta-analysis reviewing 17 studies that included over 90 million people aged 40 or older.
Traffic-related air pollution
Different sizes of airborne particulate matter (PM) can be distinguished, but the researchers focused on the so-called PM 2.5 size (meaning particles with a diameter smaller than 2.5 micrometers but larger than 0.1 micrometers).
On-road vehicles form a significant source of PM 2.5 emissions, particularly in urban areas. The results of the analysis revealed that the risk of Dementia increases considerably near busy roads with a lot of traffic.
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According to the United States Environmental Protection Agency (EPA), 12 milligrams of particulate matter per cubic meter (12 µg/m3) per year of exposure is considered safe.
The team compared the exposure to air pollution in people with and without Dementia and discovered that people who did not develop Dementia had, on average less exposure to particulate matter than the group with Dementia.
The researchers concluded that the risk of Dementia increases by 3% for each microgram of particulate matter per cubic meter (average annual exposure).
5.5 million people of the approximately 90 million study participants included in the meta-analysis developed Dementia. When processing the data, the team accounted for several factors influencing the risk of Dementia, such as age, gender, smoking behavior, obesity, and education level.
What should we do?
Although we are still talking about correlation and not causation, professor Janet Martin, one of the authors of the underlying paper, stated that ''The strength of the signal for risk is unnerving. A three percent increase in dementia risk for every unit of increased exposure is clinically relevant and will compound in the future if we fail to act on meaningful reduction in exposure now''.
In accordance with the new evidence, the researchers plan to recommend policies that significantly decrease the risk of Dementia.
However, Martin warns that without a clear strategy, Dementia will only become a bigger problem. Martin: “Dementia is like a thief in the night, robbing too many of us of what should have been a long, healthy, productive life. If there is anything we can do to mitigate this, we should act now.”
If you are interested in more details about the study, be sure to check out the paper published in the peer-reviewed journal Neurology, listed below.
Sources and further reading:
Air Pollution and Incidence of Dementia: A Systematic Review and Meta-analysis (Neurology)
The way you sleep could predict the onset of Alzheimer's Disease (Universal-Sci)
What is the difference between Alzheimer's disease and Dementia? (Universal-Sci)
Scientists may be able to predict types of Dementia more accurately based on walking patterns (Universal-Sci)
Keeping your brain lively with games may defer Alzheimer's Dementia for several years (Universal-Sci)
Alzheimer's is linked to gum disease – but bad oral health is not the only culprit (Universal-Sci)
People living in rural areas may be at lower risk of Alzheimer's disease (Universal-Sci)
The contribution of motor vehicle emissions to ambient fine particulate matter public health impacts in New York City: a health burden assessment (Environmental Health)
Dementia - Key facts (WHO)
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