Long-Term Air Pollution Exposure and Brain Structural Decline: A Longitudinal Analysis

Air pollution is an increasingly recognized risk factor for late-life neurodegenerative and cerebrovascular diseases, yet its impact on brain structure remains incompletely understood.Here we investigate the association of long-term exposure to ambient air pollution with longitudinal changes in brain structure in middle-aged and older adults. In a longitudinal cohort of 4,276 middle-aged and older adults with repeated brain MRI, we quantified global, grey matter and white matter volumes, as well as white matter hyperintensities (WMH). Residential exposures to major air pollutants were estimated using high-resolution spatiotemporal models and linked to individual neuroimaging trajectories over follow-up. Using fully adjusted multivariable regression models, we show that higher long-term exposure to ambient particulate air pollution (PM₂.₅ and PM₁₀) is associated with accelerated loss of global and regional grey matter and greater progression of WMH burden.Our findings provide longitudinal, population-based evidence that ambient air pollution is linked to both neurodegenerative and cerebrovascular pathways of brain ageing, supporting the brain as a key target organ of air pollution and underscoring the potential brain health benefits of improving air quality.