Long-term air pollution exposure increases the risk of developing dementia, according to new research findings.
In a groundbreaking study published in The Lancet Planetary Health, researchers have identified three specific pollutants linked to an increased risk of dementia. The study, which is the largest to date on air pollution and brain health, found significant associations between long-term exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO₂), and soot (black carbon) and the development of dementia.
Fine Particulate Matter (PM2.5)
Particles with diameters of 2.5 microns or less, PM2.5 originates from sources such as vehicle emissions, power plants, factories, and wood burning. These tiny particles can penetrate deep into the lungs, causing inflammation and oxidative stress, which have been linked to the onset and progression of dementia.
Nitrogen Dioxide (NO₂)
A gas produced mainly by burning fossil fuels in vehicles and power plants, NO₂ was another pollutant found to increase dementia risk.
Soot (Black Carbon)
Particles found in exhaust fumes from diesel engines and smoke from wood fires, soot was also linked to an increased risk of dementia.
The study found that for every 10 micrograms per cubic meter (µg/m³) increase in PM2.5 exposure, there was a 17% higher relative risk of developing dementia. Similarly, NO₂ exposure increased dementia risk by 3% per 10 µg/m³, and soot increased risk by 13% per 1 µg/m³ exposure.
While the pollutants appear to have stronger ties to vascular dementia than to Alzheimer’s disease, the differences may not be significant. It is not clear when in life this exposure matters most, with researchers believing it may be a period of years or even decades.
Dr. Isolde Radford, senior policy manager at Alzheimer's Research UK, stated that air pollution is a serious and growing threat to brain health. She reiterated that far more needs to be done to tackle air pollution as an invisible threat.
Dr. Tom Russ, a dementia specialist, added that more research is needed to clarify how and why air pollution might be bad for the brain. Russ also expressed the need for a better approach to research.
The analysis has limitations, including difficulty in tracking specific pollutants, their interactions, and their effects on human health. The analysis looked at data from 51 reports spanning nearly 30 million people, mostly in high-income countries.
In response to the findings, scientists and dementia groups are calling for governments to enact stricter air quality rules and take other steps to reduce people's exposure to air pollution. Barbara Maher, a professor of environmental magnetism at Lancaster University, stated that the body has no effective defense against the ultrafine particle cocktails we generate outdoors, especially from traffic, and indoors, for example, in heating our homes using stoves.
Russ, who was not involved with the study, echoed these sentiments, stating that more needs to be done to protect the public from the harmful effects of air pollution.
- The research published in The Lancet Planetary Health indicates that long-term exposure to nitrogen dioxide (NO₂), a gas mainly from burning fossil fuels, increases the risk of developing dementia.
- In environmental science, it is crucial to understand the impact of fine particulate matter (PM2.5), especially from vehicle emissions and factories, on health-and-wellness, as they have been linked to the onset and progression of dementia.
- Therapies-and-treatments for mental-health issues and climate-change policies may find unexpected overlap, as research has shown that air pollution, including soot, poses a significant risk to brain health.
- The analysis of pollution and brain health found that diet and nutrition play a pivotal role in protecting the brain from the harmful effects of such pollutants, highlighting the interconnectedness of environmental-science, fitness-and-exercise, and health-and-wellness.
