A large-scale review by the Medical Research Council (MRC) Epidemiology Unit and the University of Cambridge has found strong evidence linking long-term exposure to outdoor air pollution with an increased risk of dementia.
The study, involving 51 studies and data from over 29 million people, concluded that pollutants like PM2.5, nitrogen dioxide (NO₂), and soot are significantly associated with cognitive decline:
- PM2.5 (fine particulate matter): ↑ 17% dementia risk
- Soot (from vehicles, wood burning): ↑ 13% risk
- NO₂ (from diesel, fossil fuels): ↑ 3% risk
These pollutants can enter the brain directly or via the bloodstream, causing inflammation similar to that in lung and heart diseases.
Expert Concerns:
- Dr. Clare Rogowski (MRC): Urged stricter pollution limits, especially targeting transport and industry.
- Dr. Haneen Khreis (MRC): Stressed the need for policy action to treat air pollution as a dementia risk factor.
- Dr. Christiaan Bredell (University of Cambridge): Called for an interdisciplinary approach, involving urban planning, environmental regulation, and healthcare.
The researchers noted that although the data mostly came from high-income countries, marginalised groups, often more exposed to pollution, remain underrepresented—calling for greater inclusivity in future research.
