Neurodegenerative hospital admissions and long-term exposure to ambient fine particle air pollution

Long-term exposure to ambient fine particle (PM_2.5) concentrations has been associated with an increased rate or risk of neurodegenerative conditions, but individual PM sources have not been previously examined in relation to neurodegenerative diseases.

Using the Statewide Planning and Research Cooperative System database, we studied 63,287 hospital admissions with a primary diagnosis of either Alzheimer's disease, dementia, or Parkinson's disease for New York State residents living within 15 miles from six PM_2.5 monitoring sites. In addition to PM_2.5 concentrations, we studied seven specific PM_2.5 sources: secondary sulfate, secondary nitrate, biomass burning, diesel, spark-ignition emissions, pyrolyzed organic rich, and road dust. We estimated the rate of neurodegenerative hospital admissions associated with increased concentration of PM_2.5 and individual PM_2.5 sources average concentrations in the previous 0-29, 0-179, and 0-364 days.

Increases in ambient PM_2.5 concentrations were not consistently associated with increased hospital admissions rates. Increased source-specific PM2.5 concentrations were associated with both increased (e.g., secondary sulfates and diesel emissions) and decreased rates (e.g., secondary nitrate and spark-ignition vehicular emissions) of neurodegenerative admissions.

We did not observe clear associations between overall ambient PM_2.5 concentrations or source-apportioned ambient PM_2.5 contributions and rates of neurologic disease hospitalizations.