Overview

• A University of Pennsylvania study of 602 brain autopsies reports a 19% higher likelihood of severe Alzheimer’s pathology for each 1 μg/m3 increase in one-year average PM2.5 exposure.
• Clinical records from a subset of 287 cases showed higher PM2.5 levels were linked to greater cognitive and functional impairment on the CDR-SB scale.
• Exposure estimates were derived from satellite and ground-monitor data based on residential location, and researchers note they could not capture individual-specific exposures such as second-hand smoke.
• A separate nationwide analysis of more than 56 million U.S. hospital records found long-term PM2.5 was associated with a 12% higher risk of hospitalization for Lewy body–related dementias, including Parkinson’s disease dementia.
• Mouse experiments showed α-synuclein clumping, medial temporal lobe shrinkage, and cognitive deficits with gene-expression changes resembling human Lewy body or Parkinson’s disease dementias, though authors caution about high-dose animal exposures and call for replication and more realistic models.