Overview
- Published in PLOS Medicine on February 17, the study analyzed 27.8 million Medicare beneficiaries from 2000 to 2018 and identified about 3.0 million new Alzheimer’s cases.
- Long-term PM2.5 exposure was associated with increased Alzheimer’s risk, with a hazard ratio of 1.085 per interquartile-range increase using a five-year moving average.
- An example estimate showed roughly an 8.5% higher five-year risk when comparing areas with about 8.2 μg/m³ to 12.0 μg/m³ of PM2.5.
- Common comorbidities mediated little of the association, with hypertension, stroke, and depression together explaining less than 5% of the link.
- The association was modestly stronger in people with a prior stroke, and researchers emphasized the study’s observational limits and the need for air-quality interventions.