Key Summary
- Long-term air pollution exposure may raise dementia risk
- PM2.5, NO₂, and soot are key contributors
- Experts urge urgent environmental and policy changes
A recent large-scale study conducted by the researchers at Cambridge University suggested longer exposure to polluted air could increase the risk of dementia in people, making interventions to control it an ‘urgent need’.
Dementia is a global health concern that affect nearly 57 million people worldwide. The figures are expected to soar to at least 150 million by 2050.
It is caused by Alzheimer’s disease, and 982,000 people suffer from it in the UK alone.
The Medical Research Council (MRC) Epidemiology and the researchers at Cambridge University examined 51 studies and data from around 29 million individuals to derive the relation between dementia and three types of air pollutants.
The study observed nearly 29 million people exposed to air pollutants for over a year in high-income countries.
Researchers said the pollutants identified in the study can reach the brain, either directly or through the bloodstream causing inflammation that leads to dementia.
They identified a matter called PM2.5 with a diameter of nearly 2.5 micrometres was emitted by vehicles, power plants, burning wood and construction sites, tiny enough to be inhaled easily.
Studies specify that by every 10 micrograms per cubic meter of PM2.5, an individual’s risk to dementia rises by 17 per cent.
The presence of Nitrogen dioxide (NO₂) in the air released from burning fossil fuels is another potential factor to increase dementia by 3 per cent.
Whereas, soot discharged by vehicles and burning wood creates 13 per cent dementia risk for the people.
Dr Haneen Khreis, from the MRC Epidemiology Unit commented that this research acts as a strong evidence to prove long-term exposure to outdoor air pollution had negatively impacted the previously “healthy” adults.
"Preventing dementia is not just the responsibility of healthcare: this study strengthens the case that urban planning, transport policy, and environmental regulation all have a significant role to play," added Dr Christiaan Bredell, from University of Cambridge and North West Anglia NHS Foundation Trust.
Experts also said that the research studied a majority of white participants from high-income countries, despite marginalised groups being equally under risk.
They urged the expansion of future studies with improved representation for a safer future.
