Overview

• The systematic review and meta-analysis pooled data from 51 studies covering over 29 million participants and found a 17% higher dementia risk per 10 µg/m³ increase in PM2.5
• A 10 µg/m³ rise in nitrogen dioxide was associated with a 3% dementia risk increase and each 1 µg/m³ of soot correlated with a 13% higher risk
• Analysis suggested a stronger effect of pollutants on vascular dementia compared with Alzheimer’s disease, though limited study numbers prevented definitive significance
• Researchers cited neuroinflammation and oxidative stress as key biological pathways by which inhaled particles may trigger or accelerate cognitive decline
• Authors called for more inclusive studies in low- and middle-income countries and among marginalized groups to inform equitable emissions policies