Air Pollution Car Emissions Significantly Raise Dementia Risk: Lancet Study

A comprehensive new study has found that regular exposure to air pollution, particularly from vehicle exhaust and fine particulate matter, can significantly increase the risk of developing dementia.

Published in The Lancet Planetary Health on Friday, the study reinforces the growing link between environmental pollution and cognitive decline.

Dementia Cases Expected to Triple by 2050

Dementia, including Alzheimer’s disease, currently affects over 57.4 million people globally. Researchers estimate that this number could nearly triple to 152.8 million by 2050.

The study warns that worsening air quality may contribute to this projected rise.

Researchers revealed that for every 10 micrograms per cubic metre increase in PM2.5 (fine particulate matter), the relative risk of developing dementia rises by 17%.

For each 1 microgram per cubic metre increase in soot, a major component of PM2.5 from sources like car exhaust and wood burning, the risk increases by 13%.

Study Calls for Cross-Sector Collaboration

“These findings underscore the need for an interdisciplinary approach to dementia prevention,” said Dr Christiaan Bredell from the University of Cambridge, who co-led the study.

“Preventing dementia is not just the responsibility of the healthcare sector. Urban planning, transportation policies, and environmental regulations must also contribute.”

Researchers explained that air pollutants trigger inflammation in the brain and oxidative stress, a chemical imbalance that can damage cells, proteins, and DNA, thereby accelerating the onset and progression of dementia.

“Tackling air pollution can deliver long-term health, social, climate, and economic benefits,” added Dr Haneen Khreis from the MRC Epidemiology Unit. “It can also relieve the burden on patients, families, caregivers, and overstretched healthcare systems.”

The research team conducted a systematic review and meta-analysis of 51 studies involving more than 29 million participants from high-income countries.

Of these, 34 studies were included in the meta-analysis: 15 from North America, 10 from Europe, seven from Asia, and two from Australia.

Further analysis showed that exposure to pollutants such as PM2.5, nitrogen dioxide (NO₂), and soot had a stronger association with vascular dementia—a condition caused by restricted blood flow to the brain—compared to other types of dementia.

The study’s authors stressed the urgency of integrating air quality improvements into broader public health strategies.

The findings serve as a call to action for governments, city planners, and health authorities worldwide to address pollution as a modifiable risk factor for cognitive diseases.

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